Set in London in the early 1960s, 'An Honest Man' sees Charles come into contact with major-league villains, including the Kray brothers, with whom in truth he feels more at ease than he does with his professional colleagues. Charles Holborne’s life is in ruins. Although acquitted of the murder of his wife, the damage to his reputation has left his barrister’s practice in tatters and he is alone, in debt, and shunned.

Out of the blue, Charles is asked to represent a fellow barrister called Robeson, a man considered to be a "villain’s" brief, with a close relationship to the notorious Krays. With no choice but to accept, Charles finds himself drawn into a world of violence, gang warfare, corruption, and vice where it is not just his reputation at stake, but his very life.