"It is, it's you two." "We could say hi to Future Us." "Amy, no!" "No!" "Her name's Alaya." "She's one of their warriors." "One of you will kill me." "If she lives, so do Elliot..." "Mum..." "And Mo.." "and Amy, because I will find them." "My death shall ignite a war and every stinking ape shall be wiped from the surface of my beloved planet." "We return their hostage, they return ours." "Nobody dies today." "ELDANE:" "This is the story of our planet, Earth, of the day 1,000 years past when we came to share it with a race know as Humanity." "It is the story of the Doctor who helped our races find common ground and the terrible losses he suffered." "It is the story of our past and must never be forgotten." "This place is enormous and deserted." "The majority of the race are probably still asleep we need to find Amy, looking for heat signature anomalies." "But, Doctor, how can all this be here?" "I mean, these plants." "Must be getting closer to the centre of the city." "You're sure this is the best way to enter?" "Front door approach!" "Definitely." "Always the best way..." "'Hostile life force detected, area 17.'" "Apart from the back door approach, that's also good, sometimes better." "'Hostile life force detected, area 17.' Doctor!" "'Hostile life force detected, area 17.'" "We're not hostile, we're not armed!" "We're here in peace!" "Don't you come near me with that!" "From the clothing, the human female appears to be more resistant to the cold than the male." "I dressed for Rio!" "Leave her alone!" "You got me!" "Argh!" "Decontamination complete." "Commencing dissection." "'Area 17 incursion, species diagnostic requested." "Yeah!" "And stay out!" "Ha-ha!" "How did you get that?" "You never picked a lizard man's pocket?" "Come on, before he gets back." "That creature, do you think it was an alien?" "Any more of them do you think?" "Do you think the Earth's been invaded?" "Don't know." "But I know someone who could have some answers." "We need to get back to the surface and find him." "I wonder where this leads." "Maybe it's a way out of here." "Oh, my God, no." "What is it?" "It's my son." "It's Elliot What've they done to him?" "No!" "He's in there!" "We have to get him out!" "Elliot!" "Elliot, it's Dad!" "PA: 'Access denied." "Unauthorised genetic imprint.'" "Seriously." "We can't get in." "That's my boy in there!" "These screens, they're monitoring something." "I think they're vital signs - heartbeats, pulses." "Why else would he be wired up?" "He's still alive." "All right." "We find weapons, get that creature from the lab and force it to release Elliot, yeah?" "Yeah, trust me we'll get him out." "Ambrose." "You lied." "You told us you were the police." "It was a misunderstanding..." "Who are you?" "You and the Doctor?" "Why is this happening to us?" "What did we ever do?" "The Doctor'll get your son back, I promise." "In the meantime, we take turns guarding the creature." "So that's it?" "We sit and wait." "And then we exchange her for your family." "I promise you Ambrose, I'd trust the Doctor with my life." "We stick to his plan." "We keep that creature safe." "Argh!" "How can they have escaped?" "This proves all prisoners should remain under military guard." "I'm sure you'd prefer to be in charge of everything and everyone, Restac." "But we rank the same." "THE DOCTOR SCREAMS" "Is there any word from Alaya?" "No." "It's fine to show concern, you know." "She's part of your gene-chain." "Uh!" "I'm Decontaminating now." "Decontamination!" "No, no, no!" "Why aren't you dead?" "You're carrying my venom in your blood." "But you should have died." "Why aren't you dead?" "Show me." "How does it feel, ape?" "Like it's burning in my blood." "Please." "If you help me, I can help you." "If you could cure me, I could help you escape." "You see?" "You beg, and offer betrayal, so early!" "Why would I want to escape when I can watch you die?" "The first ape death of the coming war." "Its all right." "It won't harm you." "I'm only neutralising all your ape bacteria." "I'm not an ape!" "Look at the scans!" "Two hearts!" "Totally different!" "Totally not ape!" "Remove all human germs, you remove half the things keeping me alive." "No, complete the process." "Oh, that's much better, thanks!" "Not got any celery, have you?" "No, no, not really the climate, tomatoes, though, you'd do a roaring trade in those." "I'm the Doctor, oh, and there's Nasreen, good!" "Oh, a green man." "Hello, who are you?" "Restac." "Military commander." "Oh, dear, really?" "There's always a military, isn't there?" "Your weapon was attacking the oxygen pockets above our city." "Oxygen pockets!" "Lovely!" "Oooh, but not so good with an impending drill!" "Now it makes sense!" "Where is the rest of your invasion force?" "Invasion force?" "Me and lovely Nasreen?" "No!" "We came for the humans you took." "And...to offer the safe return of Alaya." "Oh, wait, you and she, what is it, same genetic source?" "Of course you're worried, but don't be, she's safe." "You claim to come in peace, but you hold one of us hostage." "Wait, wait, we all want the same thing here." "I don't negotiate with apes." "I'm going to send a clear message to those on the surface." "What's that?" "Your execution." "Yes..." "These chambers are all over the city." "Uh!" "Turn it off quick!" "They're not moving." "Maybe they're asleep." "Let's have another look." "No, Amy, don't look!" "Amy, what are you doing?" "Get out of there." "(Some sort of suspended animation.)" "I wonder what these are." "The Doctor would know." "The Doctor always knows." "Hey, look." "Wait..." "I've got it." "It's how they came up to the surface." "Some sort of powered transport discs." "It's our way out of here." "Even better, weapons, come on, now we can fight back." "Which way now?" "Door at the end." "Are you sure?" "Nope!" "Wow." "Yeah." "We don't stand a chance." "We have to find the Doctor." "Dad, are you all right?" "Dad!" "Ambrose, I'm fine!" "Leave me alone." "You are not fine." "Let me..." "Let me look." "Get off!" "Let me look." "Oh, my God, Dad." "I don't know what's happening to me." "It's going to be fine." "First thing is bring this temperature down, get you resting." "These must be the only ones awake, the others must still be in hibernation." "So, why did they go into hibernation in the first place?" "Their astronomers predicted the planet heading to Earth on a crash course." "They a built life underground and put themselves to sleep for millennia in order to avert what they thought was the apocalypse." "When in reality, it was the moon, coming into alignment with the Earth." "How can you know that?" "Long time ago, I met another tribe of homo reptilia, similar, but not identical." "Others of our species have survived?" "The humans attacked them." "They died, I'm sorry." "A vermin race." "What's the cure?" "What?" "I saw what you've done to my dad." "What's the cure?" "Why would I tell you?" "Cos if you don't, I'm going to have to use this on you." "Now you reveal yourselves." "First you take my son, now you hurt my dad." "I'm just protecting my family here." "That's all." "I don't want to use it." "I want you to put things right." "Use it." "What?" "Use it on me." "But you're too afraid." "A woman who can't even protect her own child must be too weak to..." "ZAPPING AND SHE SHRIEKS I didn't want to do that." "Are you all right?" "Tell me, what's the cure for my dad?" "He's vermin." "He deserves a painful death." "I'm giving you a chance." "I knew it would be you." "The one with the most to lose, the weakest." "ZAPPING" "I'm a nurse, you should've told me." "SCREAMING IN DISTANCE" "Ambrose..." "What've you done?" "She kept taunting me about Mo and Elliot and you." "ALAYA GROANS" "We have to be better than this!" "She wouldn't tell me anything." "I thought sooner or later, she'd give in." "I would've done." "I just..." "I just want my family back, Dad." "RORY:" "I'm sorry." "How do we help you?" "Tell us what to do." "I knew this would come." "And soon the war." "You're not dying." "I'm not going to let you, not today..." "ALAYA GROANS LOUDLY" "You're not authorised to do this!" "I'm authorised to protect the safety of our species while they sleep." "Oh, lovely place, very gleaming." "This is our court and our place of execution." "Let them go!" "Amy Pond, there's a girl to rely on." "You're covered both ways, so don't try anything clever, buster." "Mo!" "Now let them go." "Or I shoot." "I'm warning you!" "Don't you touch her!" "And you?" "All right, Restac." "You've made your point." "This is now a military tribunal." "Go back to your laboratory, Malohkeh." "This isn't the way." "Prepare them for execution." "OK, sorry, as rescues go, didn't live up to its potential." "I'm glad you're OK." "Me too!" "Lizard men, though!" "Homo reptilia..." "They occupied the planet before humans." "Now they want it back." "After they've wiped out the human race." "Right, preferred it when I didn't know, to be honest." "NASREEN:" "Why are they waiting?" "What do you think they're going to do with us?" "I didn't know it would go like that, Dad." "Oh, my little girl, what have you done?" "What happens now?" "BUZZING" "Oh, my God." "'Who is the ape leader?" "'" "It's them." "How are they doing that?" "How do they know that we're in here?" "'Who speaks for the apes?" "'" "Don't tell them what's happened." "I speak for the... humans." "Some of us, anyway." "'Do you understand who we are?" "'" "Sort of." "A bit." "Not really." "'We have ape hostages.'" "Doctor!" "Amy!" "Mo!" "'Mo, are you OK?" "'" "'I'm fine, love!" "I've found Elliot." "I'm bringing him home!" "'" "'Amy!" "I thought I'd lost you!" "'" "'What, cos I was sucked into the ground?" "You're so clingy." "Tony Mack!" "'" "Having fun down there?" "'Not to interrupt, but just a quick reminder to stay calm.'" "'Show me Alaya.'" "'Show me and release her, immediately, unharmed, or we kill your friends' one by one." "'No!" "' Ambrose..." "'Steady now, everyone.'" "'Ambrose, stop it!" "Get off me, Dad!" "'" "We didn't start this!" "Let Rory deal with this Ambrose, eh!" "We're not doing what you say any more." "Now, give me back my family!" "'No." "'Execute the girl.'" "No!" "No, wait!" " 'Rory!" "' - 'She's not speaking for us!" "'" "There's no need for this..." "Aim." "Listen!" "Whatever you want... we'll do it!" "Amy!" "Rory." "Don't do this." "No!" "Fire!" "Stop!" "You want to start a war, while the rest of us sleep, Restac?" "The apes are attacking us!" "You're our protector, not our commander, Restac." "Unchain them." "I do not recognise your authority at this time, Eldane." "Well, then, you must shoot me." "You woke him to undermine me." "We're not monsters." "And neither are they." "What is it about apes you love so much?" "Mmm?" "While you slept, they've evolved." "I've seen it for myself." "We used to hunt apes for sport." "When we came underground, they bred and polluted this planet." "Shush now, Restac." "Go and play soldiers." "I'll let you know if I need you." "You'll need me, then we'll see." "Nothing!" "I've got to get down there." "'Rory!" "Hello!" "' Where's Amy?" "'She's fine, look, here, she is.' Oh, thank God." "'Keeping you on your toes!" "' 'No time to chat." "Listen, you need to get down here..." "'Go to the drill storeroom, there's a large patch of earth in the middle of the floor." "'The Silurians are going to send up transport discs to bring you back 'down using geothermal energy and gravity bubble-technology." "'It's how they travel and frankly it's pretty cool." "Bring Alaya." "'We hand her over, we can land this after all." "All going to work, promise." "'Got to dash!" "Hurry up!" "'" "The moment we get down there, everything will fall apart." "We have to return her." "They deserve at least that." "I'd say, you've got a fair bit to talk about." "How so?" "You both want the planet." "You both have a genuine claim to it." "Are you authorised to negotiate on behalf of humanity?" "Me?" "No!" "But they are!" "What?" "!" "No, we're not!" "Course you are!" "Amy Pond and Nasreen Chaudhry, speaking for the planet!" "Humanity couldn't have better ambassadors." "Come on, who has more fun than us?" "Is this what happens, in the future, the planet gets shared?" "Is that what we need to do?" "What are you talking about?" "Oh, Nasreen, sorry, probably worth mentioning at this stage, Amy and I travel in time, a bit." "Anything else?" "There are fixed points through time, where things must always stay the way they are." "This is not one of them." "This is an opportunity, a temporal tipping point." "Whatever happens today, will change future events, create its own timeline, its own reality." "The future pivots around you." "Here." "Now." "So do good." "For humanity, and for Earth." "Right." "No pressure there, then(!" ")" "We can't share the planet." "Nobody on the surface is going to go for this idea." "It is just too big a leap!" "Come on." "Be extraordinary." "Oh...you..." "OK." "Bringing things to order - the first meeting of representatives of the human race and homo reptilia is now in session." "Ha!" "Never said that before, that's fab!" "Carry on!" "Now, Mo, let's go and get your son." "Oh, you know, humans, and their predecessors, shooting the breeze." "Never thought I'd see it." "So we get on those, and they take us down through the Earth?" "Geothermal gravity bubbles, or something." "They sent four." "She was our only bargaining chip." "We have to hand her back." "Wait." "Before we go down, there's something I've got to do..." "Dad, I need your help." "No!" "No way." "Please, Dad... just a precaution." "I've told you, I won't do it." "Look at what they did to you!" "This isn't about me or you." "No, it's about your grandson." "If you won't do it for me, do it for Elliot." "I know I did wrong." "But I can't lose him, Dad." "Elliot, there you are." "If you've harmed him in any way." "Of course not!" "I only store the young." "But why?" "I took samples of the young, slowed their lifecycles to a millionth of their normal rate." "So I could study how they grew, what they needed, how they lived on the surface." "You've been down here, working by yourself, all alone?" "My family, through the millennia..." "For the last 300 years, just me." "I never meant to harm your child." "Malohkeh, I rather love you." "It's safe." "We can wake him." "MALOHKEH CHUCKLES" "Come." "Elliot?" "Ell, it's Dad." "What...?" "Dad." "You're safe now." "Where are we?" "Well, I've got to be honest with you, son." "We're in the centre of the Earth... and there are lizard men." "Wow." "Elliot, I'm sorry." "I took my eye off you." "It's OK." "I forgive you." "You go on, Doctor." "I'll catch up." "'Storage facility 19 operational.'" "We lived on the surface of the planet, long before you did." "Our sole purpose has been to return to our rightful place." "And we've got a planet that can't already sustain the people who live there." "And you want to add a whole other species, to drain resources..." "'As I sat there that day across the table from the humans the future 'of both species and of our beloved planet Earth rested in our hands, 'but as the discussions went on, I began to despair about whether we would ever find any common ground," "'as ambassadors for our species we all had too much to lose.'" "So, erm, what about the areas that aren't habitable to us?" "Australian outback," "Sahara desert, Nevada plains..." "They're all deserted." "Yes, fine, but what happens when their population grows and breeds and spreads?" "And anyway, what benefit does humanity get, and how would we ever sell this to people on the surface?" "If I could get a word in, maybe I could tell you." "You give us space, we can bring new sources of energy, new methods of water supply, new medicines, scientific advances." "We were a great civilisation." "You provide a place for us on the surface, we'll give you knowledge and technology beyond humanity's dreams." "We work together, this planet could achieve greatness." "OK." "Now I'm starting to see it." "Oh, yeah." "APPLAUSE" "Not bad for a first session." "More similarities than differences." "WHOOSHING" "The transport has returned." "Your friends are here." "That's not right." "What are you doing?" "!" "Protecting our race against the apes." "You can't do this!" "You're a good scientist, Malohkeh, but this is war." "Argh!" "Here they are." "Mum!" "AMY:" "Rory!" "Something's wrong..." "Doctor, what's he carrying?" "No." "Don't do this." "Tell me you didn't do this." "What did you do?" "It was me." "I did it." "Mum?" "I just wanted you back." "I'm sorry." "I didn't know." "You have to believe me, they're better than this." "This is our planet!" "We had a chance here." "Leave us alone." "In future, when you talk about this, you tell people there was a chance but you were so much less than the best of humanity." "My sister." "SHE WAILS" "And you want us to trust these apes, Doctor?" "One woman." "She was scared for her family." "She's not typical." "I think she is." "One person let us down." "But there's a whole race of dazzling, peaceful human beings up there." "You were building something, here, come on...an alliance could work." "It's too late for that, Doctor." "Why?" "Our drill is set to start burrowing again in... 15 minutes." "What?" "What choice did I have?" "They had Elliot." "Don't do this, don't call their bluff." "Let us go back." "And you promise to never come to the surface ever again." "We'll walk away, leave you alone." "Execute her." "No!" "Everybody, back to the lab!" "Run!" "Execute all the apes!" "This is a deadly weapon - stay back." "Take everyone to the lab!" "I'll cover you!" "Go!" "Go!" "Ah-ah!" "Stop right there!" "Or I'll use my very deadly weapon again." "One warning, that's all you get." "If there can be no deal, you go back into hibernation." "All of you." "Now." "This ends here." "No." "It only ends with our victory." "Like I said... one warning." "Elliot, you and your dad keep your eyes on that screen." "Let me know if we get company." "Amy, keep reminding me how much time I haven't got." "OK, 12 minutes till drill impact." "Tony Mack, sweaty forehead, dilated pupils, what're you hiding?" "Tony!" "What happened?" "!" "Alaya's sting." "She said there's no cure." "I'm dying, aren't I?" "You're not dying, you're mutating." "How can I stop it?" "Decontamination program!" "Might work - don't know." "Eldane, can you run the program on Tony?" "Doctor, shedload of those creatures coming our way!" "We're surrounded in here!" "So, question is, how we do stop the drill, given we can't get there in time?" "Plus also, how do we get out, given that we're surrounded?" "How d'you feel about an energy pulse, channelled up through the tunnels to the base of the drill?" "To blow up my life's work?" "Yes." "Sorry." "No nice way of putting that." "Right, well, you're going to have to do it before the drill hits the city, in..." "11 minutes, 40 seconds..." "Yes!" "Squeaky bum time!" "Yes, but the explosion is going to cave in all the surrounding tunnels." "We have to be on the surface by then." "But we can't get past Restac's troops." "I can help with that..." "Toxic Fumigation - an emergency failsafe meant to protect my species from infection." "A warning signal to occupy cryo-chambers." "After that, citywide fumigation, by toxic gas." "Then the city shuts down." "You could end up killing your own people." "Only those foolish enough to follow Restac." "Eldane, are you sure about this?" "My priority is my race's survival." "The Earth isn't ready for us to return yet." "No. 10 minutes, Doctor." "But maybe it should be." "So here's a deal." "Everybody listening." "Eldane, you activate shutdown..." "I'll amend the system, set your alarm for 1,000 years' time." "1,000 years, to sort the planet out." "To be ready." "Pass it on." "As legend, or prophesy, or religion, but somehow, make it known." "This planet is to be shared." "Yeah." "I get you." "Nine minutes, seven seconds." "Yes, fluid controls, my favourite!" "Energy pulse timed, primed and set." "Before we go, energy barricade, need to cancel it out - quickly." "HIGH-PITCHED WHINING" "Fumigation pre-launching." "There's not much time for us to get from here to the surface, Doctor!" "Ah-ha, super-squeaky bum time!" "Get ready to run for your lives." "Now..." "But the decontamination program on your friend hasn't started yet." "Well, go." "All of you!" "Go." "No, we're not leaving you here!" "Granddad!" "Eight minutes, 10 seconds." "Now you look after your mum." "You mustn't blame her." "She only did what she thought was right." "I'm not going to see you again, am I?" "I'll be here." "Always." "I love you, boy." "You be sure he gets home safe!" "This is my fault." "No, I can't go back up there." "I'd be a freakshow." "The technology down here's my only hope." "I love you, Dad." "Go." "Go." "Come on.." "Go on." "'Toxic fumigation initiated." "'Return to cryo-chambers.'" "No!" "'Toxic fumigation initiated.' No!" "'Return to cryo-chambers.' This is not the order!" "'Toxic fumigation initiated.' They're going!" "We're clear!" "OK." "Everyone follow Nasreen." "Look for a blue box." "Get ready to run." "I'm sorry." "I thought for a moment, our race, and the humans..." "Yeah." "Me too." "Doctor!" "We've got less than six minutes." "Go!" "Go!" "I'm right behind you!" "Let's go." "I'm not coming either." "What?" "Oh, for goodness' sake!" "We're going to hibernate with them, me and Tony." "Doctor, you must go!" "I can be decontaminated when we're woken." "All the time in the world." "But..." "Nasreen... you..." "No." "This is perfect." "I don't want to go." "I've got what I was digging for." "I can't leave when I've only just found it." "Doctor!" "Thank you, Doctor." "The pleasure was all mine." "Come and look for us." "ALARM BLARES" "'So, the Doctor sent our warriors back to their rest on the promise of future harmony with humans.'" "'Immediate evacuation...'" "'Toxic fumigation is about to commence.' Other way, idiot!" "'Immediate evacuation.'" "Come on!" "'Toxic fumigation is about to commence.'" "No questions, just get in!" "And yes, I know it's big!" "Ambrose, sickbay up the stairs, left, then left again... get yourself fixed up." "Come on!" "Five minutes and counting..." "Not here." "Not now." "It's getting wider." "The crack on my bedroom wall." "Two parts of space and time that should never have touched right here." "And the Byzantium." "All through the universe - rips in the continuum." "How could it be following me?" "Some sort of space-time cataclysm." "An explosion, maybe." "Big enough to put cracks in the universe." "But what?" "Four minutes 50..." "We have to go!" "The Angels laughed, when I didn't know." "Prisoner Zero knew, everybody knows, except me!" "Doctor, just leave it." "But where there's an explosion, there's shrapnel." "Doctor, you can't put your hand in there!" "Why not?" "Ahhh!" "I've got something!" "What is it?" "I don't know." "Doctor!" "She was there, when the gas started..." "She must've been poisoned." "You!" "OK, get in the TARDIS, both of you." "You did this." "Doctor!" "HE SCREAMS Rory!" "RORY GROANS" "Rory, can you hear me?" "I don't understand." "Shh-shh." "Don't talk." "Doctor, is he OK?" "We have to get him into the TARDIS!" "We were on the hill." "I can't die here." "Don't say that." "You're so beautiful..." "I'm sorry." "Doctor, help him." "If the time energy catches up with you, you'll never have been born." "It will erase every moment of your existence." "You will never have lived at all." "Amy, move away from the light, if it touches you you'll be wiped from history." "Amy, move away now." "No!" "I am not leaving him!" "We have to help him!" "The light's already around him, we can't help him." "I am not leaving him!" "We have to." "No." "Sorry!" "Get off me!" "Sorry!" "Get off me!" "No!" "No!" "No!" "Let me out, please let me out..." "I need to get Rory." "That light, if his body's absorbed" "I'll forget him." "He'll never have existed." "You can't let that happen." "What are you doing?" "Doctor!" "No!" "METALLIC THRUMMING" "No!" "No!" "Doctor, we can't just leave him there." "Keep him in your mind." "Don't forget him." "If you forget him, you'll lose him forever." "On the Byzantium, I still remembered the Clerics because I am a time traveller, now you said." "They weren't part of your world." "This is different..." "this is your own history changing." "Don't tell me it's going to be OK." "You have to make it OK." "It's going to be hard, but you can do it, Amy." "Tell me about Rory." "Fantastic Rory, funny Rory, gorgeous Rory." "Amy, listen to me." "Do exactly as I say." "Amy, please." "Keep concentrating." "You can do this." "I can't." "You can." "You can do it." "I can't help you unless you do." "Come on." "We can still save his memory." "Come on, Amy." "Please..." "INAUDIBLE" "Come on, Amy, come on." "Amy, please." "Don't let anything distract you." "Remember Rory." "Keep remembering, Rory is only alive in your memory." "You must keep hold of him." "Don't let anything distract you." "Rory still lives in your mind." "SLAM!" "What were you saying?" "I have seen some things today, but this is beyond mad." "Doctor!" "Five seconds till it all goes up!" "All Nasreen's work just erased." "Good job she's not here to see it She's going to give Tony hell when they wake up." "You could've let those things shoot me." "You saved me." "An eye for an eye." "It's never the way." "Now you show your son how wrong you were." "How there's another way." "You make him the best of humanity... ..in the way you couldn't be." "You're very quiet." "Oh!" "Hey!" "Look!" "There I am again!" "Hello, me!" "Are you OK?" "I thought I saw someone else there for a second." "I need a holiday." "Didn't we talk about Rio?" "You go in." "Just fix this lock, keeps jamming." "You boys and your locksmithery." "ELDANE: 'Now as my people awaken from their 1,000 year sleep ready to rise to the surface 'my thoughts turn back to the Doctor, the losses he suffered then 'and the greater loses that were still to come.'" "To me, Van Gogh is the finest painter of them all." "Look there..." "the window of the church." "Is it a face?" "Yes, and not a nice face at all." "We need to talk to Vincent van Gogh." "Wakey!" "Wakey!" "'There's so much more to the world than the average eye's allowed to see.'" "What monster could have done this?" "The eyes without mercy." "If we're not careful the net.. result of our present little trip will be the brutal murder of the greatest artist who ever lived." "Can you breathe a little quieter, please?" "No!" "I know how it will end." "Doctor!" "Amy!" "No, no, no!" "It will not end well." "Subtitles by Red Bee Media Ltd" "E-mail subtitling@bbc.co.uk"