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 BakerThe Doctor
Matthew WaterhouseAdric
Sarah SuttonNyssa
Janet FieldingTegan Jovanka
Anthony AinleyThe MasterDelore WhitemanAunt Vanessa
Tom GeorgesonDetective Inspector
John FraserThe MonitorChristopher HurstSecurity GuardAdrian GibbsThe Watcher (uncredited)
Peter DavisonThe Doctor
Peter PrattThe Master (archive footage)
Bruce PurchaseThe Captain (archive footage)
Michael WisherDavros (archive footage)
Valentine DyallThe Black Guardian (archive footage)
