The Sour Note (short story)

 was an illustrated short story in the 1968 Doctor Who Annual, featuring the Second Doctor, Ben and Polly.

Summary
After landing on a strange planet, Ben gets an almost uncontrollable urge to go running, claiming that he's failing to get proper exercise in the TARDIS. The Doctor opens the doors and soon Ben is off out of the nervous view of Polly.

The Doctor suggests that he and Polly should get some exercise, too, so they walk briskly after their companion. Soon, however, they encounter a giant, towering, metal grasshopper. The Doctor surmises it's likely a robot, so the faraway Ben is likely not in danger of dying by contact with this robot. But he still might be somehow captured by one. The Doctor and Polly therefore go in search of whatever is controlling the robot. They find what appears to be an underground entrance nearby, but the swift insectoid robot prevents their progress towards it.

As he studies the robot's movements, the Doctor notices a series of musical notes in the air that seem to be controlling it. He therefore pulls out his recorder and emulates the notes. He then lures the creature back to the TARDIS so that he can learn more about it with his instruments. When they arrive, the robot is beating down on them, and they narrowly enter the TARDIS in time. To their shock, they find Ben safely inside the TARDIS. He's been waiting there quite some time for them. Outside, the robot tries, without success, to destroy the TARDIS, until the Doctor simply dematerialises it, and the travellers speed off towards another adventure. The exasperated Doctor, well-winded from his run from the robot, advises Ben that if he'd like to run in future, he'll just have to jog 20 times around the interior of the TARDIS.

Characters

 * Second Doctor
 * Ben Jackson
 * Polly Wright
 * an insectoid robot

Continuity

 * Ben's need to get out of the TARDIS so he can run and exercise seems at odds with later notions of the almost infinite amount of space in the TARDIS. (DW: The Invasion of Time, Castrovalva (TV story) and others) However, to this time in the programme's history, it had not been posited that the TARDIS had a vast interior — merely that it was "bigger on the inside
 * The Doctor has never been to this planet before.
 * The Doctor refers to his recent regeneration as "reincarnation".
 * The Doctor unusually refers to Polly as "Poll", just as Ben often does.

Timeline
In broad terms, this story occurs between the televised episodes, The Power of the Daleks and The Highlanders. Its place amongst non-televised adventures is harder to assess, as there's little in the way of continuity with other stories. The only real bit of continuity in the story is that the Doctor is still talking about his regeneration as if it's recently occurred. One possible placement is:
 * This story occurs after TN: Wonderland
 * This story occurs before DWAN: The Dream Masters