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.
Tom Baker
as The Doctor
Matthew Waterhouse
as Adric
Sarah Sutton
as Nyssa
Janet Fielding
as Tegan Jovanka
Anthony Ainley
as The Master
Delore Whiteman
as Aunt Vanessa
Tom Georgeson
as Detective Inspector
John Fraser
as The Monitor
Christopher Hurst
as Security Guard
Adrian Gibbs
as The Watcher (uncredited)
Peter Davison
as The Doctor
Peter Pratt
as The Master (archive footage)
