Logopolis: Part Four 1981
8.1 304 With the universe collapsing, the Doctor forms an uneasy alliance with the Master to save it. In case all does not go well, the Watcher takes the Doctor's companions to a safe place, but his plans for them don't stop there. The one hope for all lies back on Earth.
Runtime: 25 min
Starts: Tom Baker, Peter Davison, John Fraser, Anthony Ainley
Director: Peter Grimwade