It's December 1999, and strange things are happening as the new millennium nears. A British police box appears from nowhere in San Francisco's Chinatown and the mysterious man inside it is shot down in the street. Despite the best efforts of Dr Grace Holloway, the man dies and another stranger appears, claiming to be the same person in a different body: a wanderer in time and space known only as the Doctor.

But the Doctor is not the only alien in San Francisco. His deadly adversary the Master is murdering his way through the city and has taken control of the TARDIS. The Master is desperate to take the Doctor's newly regenerated body for himself, and if the Doctor does not capitulate, it will literally cost him the Earth. and every last life on it.