Everyone has a secret- and Haley's is about to be revealed. As the students of Hillsdale High return from Thanksgving break, the past is very much part of the present. Annie has started up a club to talk about the planet's environmental past- and how it might affect the future. Coco is celebrating her past sixteen years with a lavish birthday party. Whitney and Sasha are BFFs again. And Irene and Shaun toy with the idea of getting permanent reminders of where they came from. This fall, Haley's past is coming back to haunt her. Spoiler alert: Her secret will change the way the boys at school look at her from now on.