When a stranger runs his car into a ditch in dense fog in South Wales and makes his way to an isolated house, he discovers a woman standing over the dead body of her wheelchair-bound husband, gun in her hand. She admits to murder, and the unexpected guest offers to help her concoct a cover story.

But is it possible that Laura Warwick did not commit the murder after all? If so, who is she shielding? The house seems full of possible suspects. (From AgathaChristie.com)