In an Edinburgh cellar, two gunshots ring out. Across town, Max McCall is released from prison. These two events gradually converge as Max tries to rebuild his life, while new arrival Erin is trying to save hers.

Max and Erin's relationship grows ever more complicated, as the pressure on Max from his police handler Jackie steadily increases, and he has a surprising meeting.

Max and Jake pick up arguments old and new, while the Lynch family face their darkest secret. Max offers Erin a way out but is running out of time to find one for himself.