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?Following the series ten cliff-hanger that left everybody swinging in suspense, Florence is jetting off for Christmas, leaving the team a member down. So, the Commissioner decides to enlist the help of retired officer, Dwayne Myers (Danny John-Jules). Alongside Marlon, Dwayne employs his unique style of policing to help investigate the case. Left to their own devices, the pair struggle on the best plan of action for apprehending a suspect. As rain falls, tensions rise - but as Christmas Day approaches, will they realise they’re more like one another than they originally thought?