The Doctor and Rose Tyler are preparing to enjoy a visit to Earth's Moon, when they discover that the TARDIS has on its own volition, taken them instead to a small seaside town in present-day England.

In this town, the dead shell of a Dalek has been discovered by archaeologists in 1st century Roman ruins on the site of a decommissioned Cold War-era military bunker.

However, Kate proceeds to regenerate in much the same fashion as the Doctor, which causes her hair colour to change and — unknown to Rose — her intellect to increase exponentially.

The Doctor and Rose eventually reunite at the dig site, where Kate reactivates the Dalek, causing it to also regenerate.

Rose and the confused Kate escape, while the Doctor tries to unsuccessfully disable the revived Dalek before it can go on a killing spree.