In debt to loan shark Fran, gang footsoldier Darren finds he has no choice other than to turn back to his former mentor, northside kingpin John Boy Power. Under pressure from the cops and doing way too much cocaine, John Boy is becoming paranoid and erratic. John Boy agrees to take on Darren’s debt in return for absolute loyalty – the deal with the Devil done, Darren is back on the team...

When a container of drugs is busted at the docks, John Boy decides to double cross Fran on their deal. Fran retaliates against John Boy. John Boy is furious and orders Nidge to pipe bomb Fran's house leaving Fran determined that the escalating gang war will not end until he has revenge.

The crew are in festive spirits as Trish has the baby on Christmas Eve, while Rosie has come back to Dublin and Darren falls in love with her all over again. However the gang war is still raging, and John Boy orders Tommy – already caught between his friendship with Debbie and his worries about Siobhan’s money runs – to kill Fran. The hit goes wrong, and someone else becomes fatally caught up in the aftermath.

As tensions come to a head the gang threatens to implode: Luke's obsession with Mary is becoming more dangerous, while Siobhan's panic attack at the airport could get Tommy killed. Paranoid John Boy finally tips over the edge of sanity when he finds Debbie taking heroin.