Marina (Anna Friel) & Holly (Michelle Williams) are two best friends growing up in the London suburbs of the 1970s. As teenagers they experiment with drugs & boys, their close bond seeing them through all kinds of trouble. When they later attend university together, & both begin sleeping with the same professor (Kyle Mac Lachlan), the relationship enters troubled waters. Will the girls be able to separate & start again? Will they find the courage to step out into the world alone?