San Francisco, 1999. Returning home to Gallifrey with the remains of the Master, the TARDIS is forced off course, landing the Doctor in the middle of a street gang's gun fight in San Francisco. Critically wounded in the shoot out, the Doctor regenerates to save his own life. Meanwhile, the Master has taken possession of another new body. As the clock counts down to the start of the new millennium, the Doctor has to stop the Master destroying all life on Earth. The stage is set for what could be the final battle between these arch-enemies…