Gemma and Terry spend their first Christmas together as a married couple. The duo are soon investigating festive-fuelled murders that occur on their Christmas getaway. Over the course of various Santa parades, present giving events and competitive Christmas challenges things start to take a very dark turn. Gemma tries her best to salvage their Christmas as the bodies start piling up, but can Terry finish preparing the Christmas dinner of his dreams and solve the murders in time?
Gemma achieves her dreams of becoming an official, ball busting, kick ass investigator at the Serious Crimes Agency (SCA), whilst Terry is denied the dream thanks to his colourful criminal history.