After they broke up in season 4, he started his research back up again and that's how he knew Alison was still alive. He stopped writing the book when they got serious. He knew the girls before they knew him and he had originally dated Aria for research. He wanted to be a great writer and to write a really good true mystery novel about Ali. He explains that he was dating Alison during his college years and he started writing a book on her after she 'died'. She then runs to the William Tell Lodge Ski Lift and Ezra gets on just as it starts moving. Ezra runs after her but doesn't find her. Ezra finds the keys and know its her.ДЄria then realizes she doesn't have them so she decides to run to the woods. She is still reading the draft ,when she hears Ezra's car pull up outside, Aria grabs the draft and escapes out the window but she forgets her keys. She then opens a book and finds a draft of a book that Ezra is writing about Alison. She pulls up the trapdoor and goes down to find what used to Ezra's liar empty. Aria asks him how he knew that considering it wasn't on the police report, Ezra claims that Aria must have told him, she reluctantly agrees but still seems uncertain.ДЄria goes to investigate Ezra's cabin in the woods. Ezra accidentally let slips that Spencer broke down and got sent to Radley after she saw Toby' s helmet and Tattoo on a dead body.

Ezra wants to tell her parents but Aria is convinced that Spencer is strong enough to get herself out of her situation. Even Hanna and Emily start to doubt Spencer, thinking her theories about Ezra are fake.ДЄria is at Ezra's Apartment where Aria is telling him about Spencer's crazy behavior when the liars confronted her on her drug addiction. But Aria does not believe her because of her addiction. The confrontation gets heated and to protect herself, Spencer reveals to Aria that Ezra is A. Spencer admits to taking drugs but says she's not crazy. Aria tells the girlsДЄnd they confront Spencer about it. Later Ezra tells Aria that Spencer has a medical problem and she's taking drugs. But Emily and Hanna shove her off by saying that now is not a good time to do so and that they should wait until after school. Spencer tells them that they need to tell Aria about Ezra sooner than they had planned to because it is dangerous to wait any longer. but Spencer does not seem to remember any of it.

Spencer says that it was not the time to talk about her clothes since they had an 'emergency situation.' Spencer think it's time they told Aria about Ezra being -A but Emily and Hannah think they should wait.Д®mily asks her if that's the reason Spencer called her at 4 a.m. Hanna and Emily meet her in the bathroom where they comment on her clothing. Spencer then goes to the bathroom to change into her gym shorts ,flip flops and a sweatshirt. He asks her if she spent the night at school and tries to confront her on her drug addiction but Spencer quickly gathers her belongings which includes Ali's journal and rushes out. Ezra walks in and is surprised to see her there. Spencer wakes up confused realizing that she slept the whole night at school at Ezra' s desk.

Pretty little liars season 4 episode 20