Doctor Who: Logopolis

After an encounter with the Master, an airline stewardess named Tegan Jovanka becomes an unwitting stowaway aboard the TARDIS as it travels to the planet Logopolis. There, the Doctor discovers that the Master's interference with the Logopolitans' advanced mathematics has unleashed a wave of entropy which threatens to consume the entire universe.

• Director: Peter Grimwade
• Cast: Tom Baker, Matthew Waterhouse, Sarah Sutton, Janet Fielding, Anthony Ainley, Delore Whiteman, Tom Georgeson, John Fraser