The Doctor and his friends, Ssard and Stacy Townsend, arrive in Victorian London, where they discover a spaceship which is invisible to the people of the time. They meet the ship's occupant, P'fer'd, an Equinoid. He resembles a gaudily-coloured horse. P'fer'd tells the Doctor his wife M'rek'd is missing. Stacy and some street urchins rescue M'rek'd from a freak show. However the owner of the freak show is not himself human, but a shape-shifting alien; Stacy and the urchins are attacked. P'fer'd is re-united with M'rek'd and the Doctor and Ssard with Stacy... apparently.