Sienna isn't looking forward to Christmas this year. Her mum got very sad in the summer and had to go to a special hospital while Sienna went to stay with foster parents, Ollie and Elliott. They are kind but Christmas won't be the same away from home.
On the night before Christmas Eve, Sienna receives a special visitor called Nicholas. He tells her he needs her help to make Christmas special.
Together they will go on a magical adventure, encountering other special young people along the way who will help to create the true magic of the festive season.