15. Return of the Master
Premiere: June 16, 2007
Reunited at the end of the universe, the Tenth Doctor, companion Martha Jones (Freema Agyeman) and time-traveling rake Jack Harkness (John Barrowman) find the last surviving humans bunkered in an old rocket silo, where Professor Yana (Derek Jacobi), an elderly scientist, is attempting to repair a vessel meant to convey everyone to safety. When a familiar watch causes Martha to stir a vague memory, Yana learns that he is actually the Master; in a young, virile regenerated body (John Simm) he sets out to conquer 21st-century Earth.