This is the part that frustrates fans to this day. The Alison/Ezra history is arguably a bigger red flag than anything else Ezra did. Yet, the narrative treats it as a footnote.
The reveal of their relationship in Season 4 recontextualized everything the audience knew about Ezra: alison and ezra pretty little liars
To achieve this, Ezra systematically tracked Alison and her friends. He utilized advanced surveillance equipment, hired operatives, and intentionally took a job at Rosewood High School to get closer to the core mystery. When he discovered Alison’s real age during their summer fling, he allegedly ended the physical relationship, but his obsession only intensified. He used her, and subsequently her best friends, as literary lab rats. Psychological Dynamics: Power, Manipulation, and Control This is the part that frustrates fans to this day
He accumulated journals, photographs, and police reports, essentially acting as a parallel investigator to the mysterious "A." The reveal of their relationship in Season 4
The biggest plot twist regarding Alison and Ezra arrived in the back half of Season 4. The Liars (and the audience) discovered that Ezra wasn’t just a boyfriend with a past; he was a investigator operating a highly sophisticated surveillance network.
Alison and Ezra's history is the dark engine that drove the middle seasons of Pretty Little Liars . It serves as a reminder that in Rosewood, the monsters weren't just wearing black hoodies; sometimes, they were sitting at the front of the classroom writing novels.
When Alison finally returned to Rosewood, her interactions with Ezra were strained and dripping with unresolved tension. She knew he possessed the power to expose her secrets, yet she also knew how to appeal to his guilt to keep him quiet.