Londoner Mervin Wilson ruffles some feathers as he clashes with the island’s way of life. But he quickly sinks his teeth into one of the team's most puzzling murder cases yet: three men, all unconnected apart from the fact that they’re dressed as Santa Claus, and seemingly all shot with the exact same gun at the exact same time. As Mervin wrangles this impossible murder, his colleagues struggle with their new boss’s unusual working methods. And Dwayne’s Christmas with his father doesn’t exactly go to plan…