After a year in reform school (in Maine), Toby returns to Rosewood where he is treated as a social pariah, and suspected of being an "A" - by The Liars - and also Alison's murderer (by the whole town).
He convinces the girls otherwise, starting with Emily Fields when he befriends her.
Alison and her friends tried to get revenge on him by throwing a stink-bomb into the Cavanaugh's garage, which set the garage on fire and blinded Jenna, in the process.
It is unknown whether or not Alison actually knew Jenna was inside.
It is also unknown whether anyone else was inside the garage Alison blackmailed Toby into taking the blame for Jenna's "accident", by saying that she would tell the whole town about their affair.
"A" tortures him with information about his mom's supposed suicide, in which he makes deals with the devil.
He gives the RV to "A" and Spencer is upset because it could have given them information.