Welcome to The Vault—jokingly known as 'The Museum of Terrors'—a high security establishment where UNIT keeps all of its alien artifacts. New recruit Warrant Officer Charlie Sato is given a guided tour by Captain Ruth Matheson, and the archive reveals some dark secrets. An army jacket, a painting, crystal and a wax cylinder all hold a grave significance, and their stories are told by the Doctor's companions: Steven Taylor, Zoe Heriot, Jo Grant and Romana...