In the former mining town of Black Lake on the west coast of Canada, there is a story about a shipwreck. All those aboard died, except an unnamed man who staggered ashore. His descendants have a unique ability: once in their lives – and only once – they can unwind the events of the previous six hours.

More than two hundred years later, Ella Manning, marine biologist and part-time police constable, is attending a party at Black Lake Manor, the cliff-top mansion of the town’s divisive local billionaire. With a raging storm coming in from the Pacific, she and several other guests find themselves trapped. And when their host is discovered brutally murdered in a locked room, they turn to her to solve the crime.

Against the odds, Ella is sure she has identified the killer. But then time is unwound. With no memory of what she discovered before, her investigation begins again, with very different results. Someone is willing to use their gift to protect a killer, and everyone is a suspect.