As the Doctor says goodbye to Donna Nobel, he goes undercover at the Royal Hope hospital in London, where he meets medical student and future companion Martha Jones. The duo are whisked away with the entire hospital to the moon by an alien courier connected with the evil galactic stormtroopers the Judoon, and only the Doctor can defeat them

The Doctor must foil a plot from the mighty clan of Galactic Stormtroopers known only as the Judoon, who transport the Royal New Hope Hospital of London to the Moon. Martha Jones is a medical student who must help the Doctor - known to her as John Smith - before all hell breaks loose.