“I Know What You Did Last Summer” begins several months after the events of the finale, which took place on graduation night. Elena (Nina Dobrev) and Damon (Ian Somerhalder) have spent the summer happily in love, but things are not so great in Stefan’s (Paul Wesley) world.
Losing the girl became the least of Stefan’s problems when Silas (Wesley) revealed himself to be Stefan’s doppelganger. Now Stefan is locked in a box at the bottom of a quarry and Silas is impersonating him and testing his skills at the town’s end of summer festival.
Meanwhile, Jeremy (Steven R. McQueen) has to deal with being alive again as he hides the fact that Bonnie (Kat Graham) died in her efforts to bring him back to life. That becomes difficult when Elena and Caroline (Candice Accola) arrive at college and meet their new roommate who has taken what was supposed to be Bonnie’s place.
Matt (Zach Roerig) and Rebekah (Claire Holt) spent the summer in Europe where they met a mysterious woman named Nadia (Olga Fonda). As for Katherine (Dobrev), her first summer as a human has not gone well and she turns to Damon for help.