No sooner has the Doctor said a tear-stained farewell to Rose Tyler than he finds himself face to face with a woman dressed in a fluffy wedding frock. Who is she? And how did she get on board the Tardis? Can the Doctor get Donna to the church on time? Bride-to-be Donna mysteriously vanishes as she prepares to marry her boyfriend Lance in a glittering ceremony on Christmas Eve. To her complete astonishment, she suddenly appears in the Tardis with the Doctor. As the Tardis races to get to the church on time, the Doctor and Donna are closely watched by the sinister figure of The Empress of Racnoss from space. It soon becomes clear that Donna is the key to an ancient alien plan to destroy the Earth.