This is where Yuna is missing and then it goes 3 1/2 weeks later in The Alliance of Berk and Equestria.
[After the blast smoke cleared, there was no sign of Yuna.]
Princess Luna: Yuna! [coughs] YUNA!! SWEETIE!!! Yu... [sees something and gasps]
[up ahead is Nightstar lying on the ground]
Princess Luna: Yuna. [runs over to the Night Fury]
[we see Nightstar's wing patch is completely destroyed while her saddle is empty.]
Princess Luna: [voice breaking] Oh, Yuna. [she gets on her knees] I did this.
[the rest of the crowd walks up]
Hiccup: Oh no.
[the other dragons then look as well]
Nightstar: [opens her eyes and looks at Luna]
Princess Luna: I'm so...I'm so sorry... To you and Yuna... [a tear streams down her cheek]
Nightstar: [unfurls her wrapped up wings, revealing she has an unconscious Yuna clutched to her body]
Princess Luna: Yuna! [grabs her and then puts an ear to her chest] Oh, she's alive! You brought her back alive!
[even the other dragons roar in glee]
Princess Luna: [pets Nightstar] Thank you... for saving my daughter, great warrior.
[3 1/2 weeks later]
[we See Yuna laying in her bed]
Nightstar: [growls as she looks at Yuna]
[she then nudges Yuna and slowly the said-foal starts to wake up]
Yuna: [stirs awake] Oh, hey Nightstar.
Nightstar: [nudges Yuna as she gets closer]
Yuna: I'm happy to see you too, girl.
[Nightstar starts to lick Yuna but then steps on her stomach]
Yuna: OW! What-- Uh, I'm in my bedroom. You're in my room! Uh... does my mama and papa know you're in here?!
Nightstar: [starts to jump around Yuna's room knocking some fo the knick knacks and other things over]
Yuna: Okay, okay-- no, Nightstar! Aw, come on... [she then hops out of her bed] [but when she opens the door, there's Monstrous Nightmare!] WHOA!! [slams door] Okay, Nightstar. Stay here. [she opens the door again]
Scootaloo: Come on, guys, get ready! Hold on tight! Here we go!
Yuna: [gasp] I'm dead!
Princess Luna: Not quite.
Princess Luna: Ever since you, Nightstar, Hiccup, and Toothless destroyed that huge dragon, we've made opeace with all other dragons and now they live with us.
Princess Celestia: Yes, turns out all we needed was a little more of... this.
Yuna: You just gestured to all of me.
King Solar Flare: Yes, and now thanks to you, an old Alliance has now returned.
[then Nightstar comes out]
Princess Luna: And we've figured out a way to fix Nightstar's wing.
Yuna: How so?
Zecora: [walks up with a bowl in her mouth] For your Night Fury dragon, I have creating a brew that can fix her wing so she won't be stuck lagging. [she then walks over to Nightstar and pours the brew into her mouth]
[then the hole on Nightstar's wing starts to heal and then it completely seals up!]
Yuna: No way!
Nightstar: [looks at her wing and then flaps it and then growls in satisfactory]
Yuna: Now you can fly on your own again!
Princess Celestia: We're keeping them all now. But first, there's one thing that must done first.
Yuna: What's that?
Princess Celestia: You'll see.