Watch Doctor Who Sampler: The Fourth Doctor

With the fate of the entire universe hanging in the balance, the Doctor and the Master are forced to collaborate and return to Earth to carry out their plan.

The Master is loose on Logopolis and is determined to learn the planet's secret, but there is more at stake than he realizes.

The Doctor travels to the planet Logopolis in the TARDIS where a series of fateful events are set in motion.

Deciding to repair the TARDIS's chameleon circuit, the Doctor goes to Earth to find a real police box. But an old enemy is one step ahead of him.

The Doctor races to avert a nuclear holocaust. The robot, distraught over killing its creator, takes Sarah hostage and goes on a rampage.

Sealed inside an underground bunker, Miss Winters issues her demands to the world's leaders, threatening a devastating nuclear strike if her demands are not met.

Using the deadly disintegrator weapon, the robot steals the destructor codes. Harry Sullivan is sent to infiltrate Think Tank to discover the truth.

UNIT are called in when top secret plans and valuable equipment is stolen from high security establishments. The newly regenerated Doctor suggests that the thief may not be human.

As the Fourth Doctor, played by Tom Baker, donned his scarf, left planet Earth and returned to space, he created an ever-lasting iconic image of the wandering time traveler. Featuring Tom Baker and Louise Jameson join The Doctors Revisited as we take a look at the most alien Doctor to date, K-9 the robotic dog and Davros the menacing creator of the Daleks!