When Dorothy Guildford is found stabbed to death in her home, all signs point to her husband, Peter. The forensic psychologist is convinced there's more to the case that meets the eye but Police Scotland are certain they have their man. While DC Kirsty Wilson searches for evidence that will put Peter away for good, she is shocked to discover a link with a vast human-trafficking operation that Detective Superintendent William Lorimer has been investigating for months.

But before they can interrogate him, Peter is brutally attacked. With one person dead and another barely hanging on, the clock is ticking for DC Wilson and DSI Lorimer. And the stakes grow higher still when one of their own is kidnapped .