Parts: 2
Writer: David Whitaker
Airdates: 8 February 1964 - 15 February 1964
Production Code: C

Alternate Title: Inside the Spaceship
Episode Titles: The Edge of Destruction; The Brink of Disaster

Doctor: first
Companions: Susan, Ian, Barbara

Story: During an attempt to return the TARDIS to London 1963, explosions knock the Doctor and his companions unconscious. When Ian and Barbara awake, they experience a period of complete disorientation before finally realizing where they are. Susan is very concerned for her grandfather, who remains unconscious due to a nasty cut on his head. While the Doctor recovers, the other crew members experience some very strange events. Susan goes to fetch water for the Doctor's cut, and although the food machine delivers it, the display reads "empty". Upon her return, the main doors open, even though the ship is still in flight.

Having experienced neck pains earlier, Susan collapses. Ian carries her off to rest and gets her some water, and when he returns with it, a confused Susan threatens him with a pair of scissors before turning them homicidally on her bed. Very soon, tempers start to fray. The recovered Doctor suspects Ian and Barbara of sabotage, despite their protestations. Susan eventually sides with her grandfather, fearing that some presence has infiltrated the Ship and perhaps possessed one of them.

When all the timepieces in the ship melt, and the TARDIS seems about to fall apart, the crew members must come to terms with the hostility that has been bubbling under the surface of their relationships and join forces to discover what is going on, before they are all destroyed.

Notes: This is the only Doctor Who story that does not involve any actors other than the regular cast. It is also the only story set entirely inside the TARDIS. Inside the Spaceship is actually the correct title for this story.