cutegirlmayra
Sonic first meets her while running from Knuckles (who's tribe has been searching for Sonic hoping to use him to awaken Chaos), Tails warns him and they're off to stop Eggman (who has returned, fully fleshed out in his villainous true colors) who is after the emeralds (got a reading and followed it to this world)
Amy is fighting the echidnas as part of a rebel group, dedicated to peace. At first, when he meets her fighting, they lock eyes and "Oh! I just died in your arms tonight! It must have been something you said." Before that scene ends and Sonic has to snap out of it so he can help.
He tries to impress her at first, which is working until she hears they're heading back to 'Earth'.
She's immediately defensive, saying that no one of their kind could ever possibly live happily there.
Sonic is offended, telling her that Donut Lord is different.
She then gets even more upset and tries to explain he'll never belong on earth.
-Later on in the movie-
Sonic needs to convince everyone to come to earth, Eggman has stolen the Master Emerald's power and plans to summon Chaos on earth, causing a massive flood and possibly hurting his new found family.
Everyone agrees to fight… but Amy.
She wants to fight, but she says she can't go back to earth.
Finally, after stepping away, Sonic sits with her and asks her what's wrong.
She recalls the Rose family, that she was abandoned on earth too after the Echidna's kept rounding up kids with powers, she had escaped by forging her own teleport ring through her unique hammer abilities.
Mr. and Mrs. Rose took her in, they even had a little girl soon after but then the parents began to fight. Mrs. Rose didn't want Amy near the baby, acting more like she was an animal than a person. Mr. Rose and her fought constantly and Amy would take the now growing little girl out to the backyard swings. When Amy heard with her keen hearing that Mrs. Rose wanted Amy out of their home, she packed up, tucked the little girl into bed, and left the family.
Sonic tries to convince her that the Wachowskis are different, but leaves a ring and closes her hand around it to encourage her to come… and soon.
He leaves, and Amy later does use the ring to show up when the gang is in dire peril and helps fight off Eggman.
"So, there are more hedgehogs like you… how annoy… but fun! This just means more exterminating for me!" Eggman attempts to attack Amy but Sonic grabs her, holding her bridal style for the first time–leading to a scene where Amy looks up and its all sparkly slow-motion, showing her new feelings growing more strongly for him–as he saves her and thanks her for coming at just the right time.
"I know this is hard for you, but-"
She places her two fingers on his lips, shaking her head, "You're appreciative, right?"
He smiles, and the two fight.
Later, after Chaos is defeated by Sonic, Amy sighs and relaxes before hearing someone calling her name.
She looks around before turning and finding Mr. Rose racing towards her, calling out her name.
She begins to tear up and races into his arms.
"We searched high and low for you!"
"Y-…you did?"
"Amy!"
She turns and sees the little girl, giving her a hug as well. Then she realizes the Mr. Rose got a divorce and has been looking for Amy ever sense.
"You were never a wild animal or a pet to me." He places his hand on her head, "You were always, and will always be, my daughter."
Amy hugs him, and behind, standing away–is Sonic.
He seems to be responsible for finding Mr. Rose and happily nods to her with respect for the moment, he found them for her.
She moves past her loving family and hugs Sonic, "I can only think of one thing to repay you for all you've done for me."
"Ah, it's nothing, really~" Sonic scratches behind his head, but is clearly proud of what he's done until she says–
"Sonic The Hedgehog, I'm gonna marry you."
"H-hu-huh, what?!" he jolts back and sparks fill his eyes and quills for a moment, she kisses his cheek and rushes off back to her reunited family, waving.
"Consider me your self-proclaimed girlfriend, Sonic!"
Tom teases Sonic about it but Sonic gets pretty upset, running from Amy when he sees her next, but Amy continues to say that she'll marry her true blue hero.
Later on, Mr. Rose shows Amy that she and Sonic aren't the first hedgehogs to come to earth… Apparently, 50 years ago, Earth tried making their own…
A little girl, named Maria, resembling Mr. Rose's daughter is next to a black and red hedgehog… it appears something went horribly wrong…
And that's the next movie ;)b