See in the beginning Stiles and Jackson were best friends, they only stopped because their parents hated each other & displayed their hate for each other. When the Kanima happened it drew the two closer again, it wasn't Lydia who brought him back but Stiles.
When Jackson's parents made him leave, the two stayed in touch. Stiles never lied to Jackson or held info, he was the only one he told EVERYTHING to.
When the nogustine happen Stiles stopped talking to Jackson, he got worried & went to Beacon Hills. He sees Stiles before he makes the oni stab Allison when he calls Stiles name Stiles looked at him like he wasn't controlled. Like it was somebody else wearing Stiles' face.
What felt like hours but was only a few seconds passed by and Stiles seemed to understand who is he. Stiles face shifts into normal Stiles, he says, "Jackson" then passes out.
Stiles whimpered out he can't be both and Jackson understood. He told Scott to bite Stiles at first he was hesitant until Jackson says it's the only way to help him.
When Scott bites him a shadow overtakes his body and a single fly came out, Derek captures it with a jar. Jackson carries Stiles away ignoring the pack. He takes him to his house knowing the sheriff isn't here, he barely is.
Jackson cuddles with him and keeps watch over him. When Stiles finally wakes up and sees Jackson he tackles him to the bed hugging and scenting him. Stiles cried & told him everything the nogustine did.
Jackson listens but never let Stiles go. Stiles loves Jackson smell, it smells like protection, understanding, and fresh water. So he buries his face into Jackson's neck until he figures it out.
S: I'm a werewolf.
J: I figured it out.
S: ...I missed you.
J: Me too.
They held onto each other tighter. Jackson finally gets up to look through his bag & present some papers to Stiles.
He knew Stiles wouldn't do it himself so he got Stiles's emancipation papers by asking for some favors, he also gave a key to his apartment.
Stiles looked at them and tackled Jackson again this time kissing him. Jackson kissed back, both expressing their feelings through it.
Stiles packs up his stuff and some of his mom's stuff than sends it to their apartment. They get the earliest plane ticket for first class than go to the airport.
As sad as Stiles, he decides it's best to leave his jeep in Beacon Hills, knowing it can't be used anymore. They leave without saying good bye or telling anyone they're leaving.