At the Secret Animal Society Sanctuary, hidden away in a remote corner of the country, Christmas is approaching. There's lots to organize with the winter weather drawing in, and all the endangered and rare animals to care for. When twins Eddie and Izzie are awakened by two yetis, they realize through sign language that a baby Bigfoot has gone missing. Eddie, Izzie, and their little brother Toby all have to get to school for the end of term costume party, so reluctantly they head out and the search continues without them. At school, Toby discovers one of the children crying outside wearing a snowman costume. It's not long before the teacher realizes what's happening and that it's not a child in costume after all! Snowball is taken to the zoo, and it's up to Izzie and Eddie, with the help of Beth from the sanctuary, to sort out a rescue plan.