Freddie is fed up because his two younger twin sisters, Phoebe and Ella, have broken his favourite toys, the Mutant Plasma Orbs (MPOs) and have made him dress up as a fairy godmother. Fortunately, his best friend Clive comes to his rescue. MPOs are electromagnetic toys the size of a cricket ball. When switched on, a small mutant creature appears inside the MPO. There are various MPOs for children to collect. Freddie only has two MPOs, known as Squirt and Puke. He is really upset that they are broken, but Clive's father is Professor Langdale, a nuclear physics professor, and so the boys ask him to fix Freddie's MPOs. Although it is Christmas Eve, Freddie is feeling sorry for himself because he has no MPOs to play with. After a series of twists and turns and a chaotic family gathering, Christmas Day arrives and Freddie is hopeful that his fixed MPOs will be returned. But there are more surprises in store as Freddie's father comes home for Christmas Day and he has a new gift for Freddie - a new type of MPO. It's not all over yet though - Great Auntie Doris has an accident, and sneaky Mr. Letcher from next door is hanging around Freddie's mother. Will they ever have a peaceful Christmas Day?