Mahmood Mattan is a fixture in Cardiff's Tiger Bay, 1952. He is a father, chancer, petty criminal. He is many things, but he is not a murderer. So when a shopkeeper is brutally killed and all eyes fall on him, Mahmood isn't too worried. Since his wife, Laura, kicked him out for racking up debts he has wandered the streets more often, and there are witnesses who allegedly saw him enter the shop that night. It is only in the run-up to the trial, as the prospect of returning home dwindles, that it will dawn on Mahmood that he is in a fight for his life - against conspiracy, prejudice and cruelty - and that the truth may not be enough to save him.