Over the years they educated the Gonds through teaching machines in the great Hall of Learning. In return, the Gonds periodically selected their two most brilliant scholars to become the 'companions' of these  mysterious beings.

But when the Doctor, Jamie and Zoe arrive on the planet, they soon discover the true evil purpose of the aliens and learn what it really means to be companions of the Krotons ...
 

And now, every year, the Gond's two greatest scholars are chosen to become companions of the Krotons. They disappear and are never seen again, but it is held to be a great honour; for only the finest are chosen.

But when the Doctor, Jamie and Zoe arrive on the planet, they discover the true, evil purpose of the aliens and find out what it really means to be the companions of the Krotons ...

Doctor Who - The Krotons, featuring Patrick Troughton in the role of the Doctor, was broadcast in 1968 and was written by Robert Holmes. This novelization is by Terrance Dicks, who has novelised over sixty Doctor Who television stories; at the time The Krotons was broadcast, he was the script editor of the series.

Doctor Who - The Krotons is available on BBC video.
 

As the TARDIS door opens onto a barren planet, the Doctor steps straight into a struggle to destroy the merciless Krotons, the unseen rulers of the Gond people. Conditioned to obey by teaching machines the Gonds put up no resistance until, with the Doctor's help, they discover exactly what has been happening to their best students.

Battling against the Krotons' vast scientific knowledge the Doctor and Zoe must stop them turning mental power into pure energy. With a brave band of Gonds and Jamie, prepared to fight to the end, it may be deafeat for the Krotons, but ultimately it will be a test of knowledge that only the Doctor can match...

Running Time: 91 mins approx
Original unedited black and white recordings.
First transmitted 28 December 1968 - January 18 1969