The pilot episode presents the viewers with the key moments leading up to Lennon's death, which kicks off the show's main plot. At their graduation party, twin sisters Alison and Lennon get into an explosive argument when Alison finds out Lennon slept with her longtime crush, Dylan. After their fight, Alison bolts out of the room, and in her haste, she takes off with Lennon's jacket. She goes and sits in her car, in desperate need of an escape from the bustling party.
Meanwhile, when Lennon's group of friends see a cop on the premise, they run to avoid getting caught because they're drunk and high on drugs. They spot Alison sitting behind the wheel in Lennon's car (dressed and styled identically to her twin sister) and naturally assume she's Lennon and ask her to drive them away from the house. Alison, already emotionally distressed about her fight with Lennon, doesn't correct them and plays along. However, when she momentarily takes her eyes off the road while driving, she winds up accidentally hitting Lennon, who was walking on the road. When they check her pulse, they find, to their horror, that she's dead. However, Lennon's friends all believe it's Alison who's died, not their friend Lennon.