A stag do goes awry when the host of their fishing trip is found harpooned on a beach the next morning. But as their boat never moved, how could any of them have done it?

It's Christmas time on Saint Marie and Neville is preparing to head to Manchester to spend the holiday with his family. But his plans are abruptly changed when a billionaire shipping magnate dies in mysterious circumstances.
Things only get stranger when a minicab driver in London receives a Christmas card with an ominous message inside that turns the entire case on its head. For Neville and the team, will this be a case they can crack together?