The Doctor meets Martha Jones, a medical student in London, under unusual circumstances when her entire hospital is transported to the Moon. Can she learn to trust this mysterious stranger to save them all?

Harry Saxon becomes Prime Minister of Britain and his reign of terror begins. The Doctor, Martha, and Jack begin to unravel his true identity and a plot to destroy the Earth that stretches to the end of time.

All hope seems lost as Earth has been conquered by the Master and his strange army. The Doctor remains his prisoner, so Martha alone must save the world.

Jeff is going on a work trip to Aberdeen with Sophie, and Mark, fearful that they will sleep together, becomes desperate to stop them.

William is working overtime handling the tragic deaths of three teens. Mary has kicked Molly out for her meddling, and she dashes William's hopes when she tells him to slow down.