When detectives John Stone and Carmen Dehan who run the Cold Cases Department at the 43rd Precinct in the Bronx choose their honeymoon together, there are three things they are very clear on: there must be good steak and whisky, it must be remote, and for two blissful weeks they must forget about work, about cold cases and about murder. So a small island off the north coast of Scotland in a 16th century castle seems to be just the job.

After all, two out of three isn’t bad.

At first the place seems idyllic: The wild landscapes are breathtaking, the northern lights otherworldly and the fire-side talk, fuelled by good whisky and good Angus steak, is fascinating. Maybe a bit too fascinating when it leads to a forty year old mystery about a man murdered, shot with a .38 in a locked room in circumstances which are, quite simply, impossible.

And when the island is cut off by a storm, and an identical murder is committed, well, what are two cold case cops on honeymoon to do…?