Father and mother form a happy little family with their children, until one day their children decide to split up. The house is cut into two equal halves. One half for brother and one half for sister. The parents are involuntarily torn apart by the divorce and are forced to swap children and homes week by week.

Jules Claus has embraced Christmas again and is getting ready for the busiest time of the year together with grandpa Noël. Everything seems to go according to plan, until Jules receives a very special letter with an intriguing question...