If any remember Karai from tmnt 2012 well she's in this story along with Slasher and many of you who don't know who he is. He was Raph's pet turtle before being mutated and gone evil then back to good. It's complicated story.
As Hiccup and Toothless were flying through the night sky between 9:45 P.M. And 10:26 P.M. The two friends were flying through over the city patrolling trying to find crime. Unknown to them they flew over an USAF airbase. As a man on the Radar he notice something (Hiccup and Toothless btw.) the Colonel walks to the Radar man. Colonel: Anything soldier? Radar man: Yeah I just picked up a strange thing flying through our air space. Colonel: One of ours? Radar man: Nothing on schedule at this time sir. Colonel: A plain? Radar man: No both too fast and too small. Colonel: We got are selfs a bogie. Scramble the jets! As the jets started to leave the air base. Hiccup felt the wind in his hair, Toothless felt the wind in his wings till they heard jet engines. Hiccup: Toothless advanced maneuver! The two try hiding in the clouds till the jets try to get a closer look. Till they saw them. Pilot 1: Gold Knight one this is Gold Knight two we have visual. I repeat we have visual. Pilot 2: Copy. Stand by to engage. Fire a warning shot. Jet two fires a warning shot but a small spark catches Toothless' prosthetic tail on fire forcing Hiccup and Toothless to fall in the water. Pilot 2: I told you fire a warning shot not a live fire! Pilot 1: I did fire a warning shot! Maybe some of warning shots must have caught something on fire.
As Hiccup and Toothless entered to water they try to swim but they couldn't. As they lost breath and fell to unconscious then something pulled them down. After a few hours Hiccup is almost waking his eyes and sees a girl almost his age, and she was cover Hiccup with bandages. Hiccup: W-w-who are you? Karai: my name is Karai. And I know who you are. Hiccup Horrendous Haddock the third. Hiccup: How do you know my name? Karai: Slasher kidnnaped a Kraang droid and interagat him do get aswers. Hiccup: Who's Slasher? Then a Giant tortoise with spike on his shell. Slasher: Karai how's our guests? Karai: He's fine and his pet's alright. Hiccup was a bit scared of him and notice the Foot Clan symbol on Karai's armor. Hiccup: Ho, great I'm back in the Foot Clan liar. Karai: No not the Foot Clan. I was raised by the Shredder until I discover the truth. That Splinter was my real father. Hiccup: Wow, wow, wow. Splinter's your dad? Karai: Yes. And yet I was stolen and raised by the Shredder. I was living a lie. Hiccup: And you big guy? Slasher: I was once Raph's pet turtle once. Until I ate some mutagin and well I became this. And I went evil till I knew the true meaning of evil and thus lost my teast for enflflickting opion it. Hiccup sees Toothless waking up Hiccup slowly gets up till he feels a pinch in his side. Hiccup: Ow! Karai: You need to take it easy you're lucky to survive the night what with the help of that sea creature the Kraang used as a gaurd dog once. Hiccup: So why did you take my shirt off? Karai: I needed to find any wounds. Also thanks to Slasher we found this medical aid. We need to get you back to the other dragon riders and the turtles. Hiccup nod in agreement. As the four across New York they notice Kraang and Foot Clan, were smuggling weapons and chemicals. Hiccup: You two see that? We got to stop them. Slasher: Are you sure about that? Because if you are. I'm in. Karai: Let's bring the pain. So the four jumped in and started to fight unknown to them the Turtles and other dragon riders were already in the fight. Astrid: Hiccup! She yelled and hugs him really tightly. Hiccup: I'm glad to see you too Astrid. Then she breaks the hug and punches Hiccup's arm. Astrid: Who are these two? Hiccup: I believe the turtles may know who these guys are. Leo explains and tells them everything.
As the Turtles entered the lair they notice April and Casey minding their own business till Slash and Karai entered the room. Though Hiccup was confused why Karai had snake eyes (I know ironic.) Karai explain that the Shredder was planing to use her as bate to lure both Splinter and the Turtles till she fell in by accident. Hiccup: So can we see your other form? I know its not a nice thing to ask but... Then Karai transforms from a human into a viper like creature and has viper heads without eyes as hands. All: Wow! Tuffnut: Man that just awesome! How do you do that?! Karai: I don't know it mus-s-s-st have append when S-s-s-s-stokmen s-s-s-s-spilled that retro-mutagin in the regular mutagin. Splinter: That mean you're half mutant and half cured. But Donatello can make a new cure right? Donnie: Maybe but it will be hard. Her cells are unstable, and unpredictable so it will be tricky. Astrid: So her DNA is like a Chinese puzzle box right? Donnie: Well when you put it like that then yes. Hiccup look at her and ask for some alone time. Hiccup: Karai can I talk to you alone in human form? Karai nod in aggrrenment then transforms into her human form. After a while both Hiccup and Karai are siting on the edges of a sewer tunnel end. Hiccup: So-o-o-o... What was it like being part of the Foot Clan I-I know it's hard but I just want to know... Karai: (Sign) It was hard I've been training since I could walk. Shredder fed me lies about my real father and I never met my mother, because Shredder said Splinter murdered her. But he was the one that kill her. Hiccup knew what it was like not growing up without a mother. Hiccup: I know how that feels. Karai turns her head and in confuson of what Hiccup said. Hiccup: I never knew my mom because when I was a baby dad said she was taken during a dragon raid, by a four x-winged dragon with an owl like head. But my mother try to protect me. the others said and during the time growing up seeing everyone with their moms and teasing me by saying my mom left me on purpose saying my mother though I was a useless son. But my dad knew better, so I guess in a way we're alike right? Karai smiles a bit. Karai: Do you have any memories of her? Hiccup: I only have a toy that she made for me when I was just a baby. (Chulickes) It scared me half to death, I conundn't sleep for a week. Karai laughed a bit Karai: Yo. Were scared of dragons? Hiccup: You have no idea. I was so little when mom. But now that I have the toy back I love it. Hiccup and Karai hugged it out as friends knowing they are alike. Then scales appred underneath the water and poped out Leatherhead. Hiccup: Wow! Karai transforms into her snake form but the mutated gator didn't attack them but over here their stories. Leatherhead: I don't wish to harm any of you. I over heard you stories and I feel sorry for you in my soul. Hiccup: Who are you and what are you. Leatherhead: My name is Leatherhead I'm an alligator, I was once a normal gator raised by a kind human boy. Till his parents found me and threw me into the sewers and that's where the Kraang found me. They did horrible experiments on me, the torgered my body. But they could not break my spirit! Hiccup: So you fought against Kraang before. Leatherhead: Many times even in their dimension X.
Meanwhile at the Foot Clan's lair the Shredder was in a angrier mood Shredder: Why isn't there my new weapons and chemicals for the mutagin? Foot solder 1: We were attacked by the dragon boy and the snake who his your former daughter and a large turtle with spikes on his back carrying a mace. Shredder heard the word former duaghter. Shredder: Karai is with the dragon brat?! Foot soldier: Yes... He said frighten. Shredder: I will deal with him and Karai personally. The rest of you will be a distraction to lure the others away. As the ninjas left, Shredder is in thought knowing his adopted daughter is with Hiccup. So he pepared himself with new armor with weapons: A samurai armor made from tank armor and jet armor and Titanum steel and for weapons a sword sharp enough to cut through tank armor, and right hand mini-gun and blads as long as three ft in length.
Back at the turtles lair they were minding their business. They suddenly hear a noise from the fron entrace and back entrance. Hiccup, Toothless, Karai, and Leatherhead took the back entrance while the others took the front. Stoick: Proctect Hiccup, Toothless, and Karai. Leatherhead: I will guard them as if they were my own children. Stoick nods Leatherhead knowing he's a good person. As the other dragon riders, and ninja turtles charge the intruders from the front entrance while Hiccup, Toothless, Karai, and Leatherhead gose for the back. As the others fight what seems like 60 Foot soldiers, and 35 Kraang they put up a good fight. While Hiccup, and his friends are in the back and find no one till an exposition came from a wall as they brace for impacted they notice it was the Shredder: I see Karai, you've taken a liking to these turtles and other mutant and even primitive Vikings. Karai: You'll pay Shredder for what you did to my real parents. Shredder: It was Homato Yoshi's fault your mother died. Hiccup: No! It was your blade that killed her she never loved you the way you wanted. She was never yours her heart belong to Splinter's she chosen him and not you. And I bet it killed you on the inside and if you couldn't have her then no one should! Shredder: Hmmm... I will have your dragons scales as a cape, and your gator friend as boots, and finally you Hiccup you'll be my personal student, or you'll die. Hiccup: I'd rather die... Shredder: That can be arranged and it's time for you to see... What an upgrade looks like. Then Shredder shows his weapons. And Letherhead, Karai, Toothless, and Hiccup stared fighting. Shredder was winning. And at the last moment Shredder grabs both Hiccup and Karai and runs off with them. As Leatherhead regains consciousness. He notice "both" Hiccup and Karai were gone. He couldn't find any tracks or any smell so here when back to the others to warn them.
At the Foot Clan lair the two were still unconscious so Shredder thought it was time. Shredder: Get Kraang Prime. The a video screen. Kraang Prime: Shredder you'd better have a good reason for calling me. Shredder: I believe it's time to go to war. Prepare your soldiers and I'll prepare mine. Kraang Prime hangs up, the Shredder turns around and look at Karai and Hiccup. Shredder: Put them in the cells. Shredder: The age of the Shredder and Kaang begins now!
Du du du duaaaa. Things are gonna get bad. So to be continued...