Oliver Nolan, a volatile homeless man wanders the streets of Dublin City during the Christmas period. After an unusual encounter with a mysterious priest called Roman, Oliver believes he is sent on a mission from God to clean up society. When he saves a young disaffected boy named Tommy from some local bullies an unlikely friendship is formed. Oliver soon realizes that Tommy's mother is an addict and his uncle Rudyard is a local drug dealer. Oliver takes it upon himself to get even with Rudyard and his gang of petty criminals for taking advantage of his only friend, Tommy.