They arrived in Hill Valley and they saw Heartless attacking Hill Valley
Ryan: Heartless! We have to find Marty and Emmet Brown!
They went off to find them and they found him at Doc's House
Marty: Look, it's Ryan and his friends!
Ryan: Hey, Marty. This is Sora, Donald and Goofy.
Doc: So what's going on?
Ryan: Well, you see there are many Heartless attacking in Hill Valley.
Doc: Great Scott! They're back again!
Marty: But who the one behind this?
Ryan: We don't know, but we have to find out.
Doc: Okay, let's go find the Culprit who's behind this.
They went off and they found it was Pete
Pete: You again!?
Sora: Not him again.
Pete: I knew you would arrived here.
Ryan: So you're the one behind all this?
Pete: That's right! Heartless!
He summon the Heartless, they are fighting it and they defeated it
Pete: I'll get you for this!
Then the Time Machine is glowing
Doc: Great Scott!
Ryan and Sora unlocked a new Gateway
Sora: A New pathway has opened.
Ryan: We have to leave, but don't worry we'll come back.
They left this world