cassie and sid are in a serious romantic long distance relationship. in "sid", the third episode, sid thinks cassie is cheating on him and becomes angry at her. cassie is also angry, but because sid does not trust her. at the end of the episode cassie takes a train from where she lives in scotland to bristol, to visit sid. she waits in his bedroom for him, but when sid enters the bedroom he is kissing michelle (not noticing that cassie is also there). in "chris", the fifth episode, cassie bitterly tells her friends that sid is together with michelle. she copes with her feelings by having sex with almost anyone, doing drugs, and partying. in "effy" sid finally confronts cassie and her bad behavior. the two get back together, but in "cassie", it is clear that cassie is still angry towards michelle. after cassie's roommate and friend chris miles dies, she runs away to new york city, where she is taken care of by a boy called adam. in the finale "everyone", in the last moment of the episode, sid looks for cassie in new york, and stops in front of the diner she works in.