For the police it was an open and shut case: Stephen Lumley was guilty of taking part in the robbery at his uncle's jewellery shop. All the evidence was against him - he was unemployed and in debt, he'd made threats in the past against his uncle, Bernard Hammond, and he'd tried to escape when the other thieves fled the scene.
Yet Lumley maintains his innocence, and the only person who believes him - apart from his wife - is his lawyer, the intuitive Rosa Epton. Rosa's efforts to learn the truth are frustrated by the elusiveness of a possible lead, so Lumley must stand trial at the Old Bailey. Undeterred, Rosa carries on her private enquiries with little success, until, that is, her lead turns up - dead.
As the police investigate, new evidence comes to light, and events take another turn when Hammond's wife is kidnapped.