We're back on the beautiful island of Saint Marie, and this time with a new detective inspector in tow. 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, are shot with the exact same gun at the exact same time. As Mervin wrangles with 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...