Plot summary
Spencer, Emily and Hanna search Ezra's classroom and find Ali's diary. Spencer takes it home with her. Meanwhile, Aria and Ezra spend time together. Tired from staying awake thanks to her prescription pills, Spencer falls into a state of trance. Spencer's thoughts become transformed into a black-and-white 1940s film noir era. Imaginary moments include Toby accusing Spencer of keeping secrets, Alison accusing Spencer of becoming dependent on the pills, and Ezra whispering to Aria that he knows Alison is still alive. Of course, none of this is real. Just before Spencer snaps out of it, Toby tells her to look at the pages in Ali's diary.
When she comes to, she goes back to Ali's diary and scans the pages using her mental revelation of Toby's insight. Spencer returns to Emily and Hanna with the diary and tells them that seemingly minor but important details have been altered. The girls realize that they were meant to find the diary and since it has been altered, Ezra knows that they know. They decide it is time to warn Aria, but when they find her, they are surprised to see that she is happy and kissing Ezra at her house. ' A' ending: A message from 'A' is shown in the dressing room in Spencer's dream.
Credits
Adapted from Wikipedia contributors, Pretty Little Liars season 4. HTML formatting and reference markers removed.