A year after his shooting, Darren is left plagued by nightmares and with one functioning lung. But he's getting his life back together, hoping to get back with his beloved Rosie (now living in London) and doing some work for up-and-coming cigarette smuggler and loan shark Fran.
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 again. The gang war is still raging. A hit goes terribly wrong.
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. John Boy finds Debbie taking heroin.