Dani is understudying the part of a witch in Macbeth: The Musical, which means Jack and Sam get the job of ensuring little brother Max does not cause chaos. Dani's most loyal viewers, the aliens, have got bored of never getting to meet their heroine and her pals, and have decided to teleport down to Earth, where they soon find themselves embroiled in Max's scheme to win the £10,000 reward from the UFO Society.

When ever-unfit Jack enters a fun run for Sport Relief, Dani and Sam are convinced he will never make it round the course and so offer to sponsor him for ridiculous amounts of money. It soon becomes clear that Jack is taking his running all too seriously. Dani decides to undermine her best friend. Meanwhile, Max sees Jack's run as the perfect way to raise some sponsorship cash for his own favourite cause - himself.