MORTAL Sin takes us on a journey of friendship and growth between the two characters Colm and Peggy in 1960s Ireland. JFK has just been shot, and the two young friends believe this calls for a day off school. They make naive attempts to resist the system and defy their elders. Though the young friends share moments of light-hearted play, their thoughts and actions are ultimately subsumed by the pervasive Catholic mindset of the era.