Lawyer Jack Lennox finds himself increasingly frustrated by the professional criminals he is called upon to defend and so stumbles upon the idea of devising the perfect crime himself... But when a plan for a theoretical bank raid is carried out to the letter, Lennox finds himself drawn into an exciting and illegal sideline as a criminal mastermind. It's a dangerous double life - and the stakes are even higher than he realises. When his secret is discovered by Assistant Chief Constable Brian Richards he offers Lennox a chance to win his freedom. Promising to hand over the top four criminal gangs in the UK, he devises one final brilliant plan. But who can he trust and which side is he really on?