Back up to: Season 18
4/4 With the fate of the universe at stake, the Doctor and the Master must collaborate.
3/4 The Master is loose on Logopolis and is determined to learn the planet's secret.
2/4 The Doctor travels to Logopolis where a series of fateful events are set in motion.
1/4 To repair the TARDIS' chameleon circuit, the Doctor goes to Earth for a real police box.