Fixing the mechanism involves a visit to Earth and a trip to the planet Logopolis - normally a quiet little place that keeps itself to itself.

But on this occasion the meddling presence of the Doctor's archenemy, the Master, ensures the disruption of normality. And even the Master is horrified by the threat of total chaos he unintentionally precipitates - until he finds a way to turnn the imminent destruction of the universe to his own advantage ...
 

For as long as anyone can remember the chameleon circuit of the TARDIS has been broken - a minor inconvenience which the Doctor now finally gets round to correcting.

But fixing the mechanism involves a visit to Earth and to the planet Logopolis - a quiet little place that keeps itself to itself.

But on this occasion the meddling prescence of the Doctor's arch enemy, the Master, ensures the disruption of normality. And even the Master is horrified by the threat of total chaos which he unintentionally precipitates.

Logopolis was the final story to feature the fourth Doctor, as played by Tom Baker.

This is a novelization by Christopher H. Bidmead of his own original script.
 

"I HAVE JUST DIPPED INTO THE THE FUTURE. WE MUST BE PREPARED FOR THE WORST."

Haunted by a shadowy watcher, the Doctor's bound for Logopolis in search for a new Chameleon circuit for the TARDIS, with a dangerous stowaway on board. Now in a new body, and bent on Universe domination, his arch enemy the Master is back with a vengeance. His plan could rock Logopolis, the keystone of life. Could this mean the unravelling of the causal nexus and the end of the Universe itself?

Originally transmited 28 February - 21 March 1981, this four part adventure marks the end of the Tom Baker era and the Doctor's fourth regeneration.

Produced by John Nathan-Turner
Directed by Peter Grimwade