Changing history is a very fanatical idea, you know.
For a show ostensibly about time travel, Doctor Who features very few stories actually about time travel. Louis Marks’ Season Nine opener, “Day of the Daleks” (Series Production Code KKK), tries to explore the paradoxical intricacies of altering history but, oddly, is kept from doing so by the lead villains, who make a rather flat return after nearly five years’ absence from the screen. For this story, about a ragtag band of guerrilla fighters in 22nd Century Earth travelling back in time to stop World War III from breaking out in the 20th Century, would have worked better without the Daleks at all.
UNIT summons the Doctor and Jo to investigate the strange appearance (and disappearance) of an armed intruder in the home of Sir Reginald Styles, a British diplomat attempting to broker a peace between China, the UK, and the rest of a world on the brink of all-out war. When the would-be assassin is later found injured in a nearby tunnel, the Doctor surmises that he’s from Earth’s future, armed as he is with a disintegrator gun, made with Welsh-mined metals, and a crude form of time machine. This conjecture is confirmed when the assailant’s accomplices show up and capture the Doctor and Jo, who have lain in wait for them in Style’s study (after helping themselves to the diplomat’s well-stocked larder and wine cellar).
Through a series of misadventures—and Jo’s on-again, off-again skill with “escapology”—both the Doctor and Jo separately wind up in the 22nd Century, Jo in the custody of the Dalek-led human government and the Doctor with the guerrillas who are, it turns out, fighting against the Dalek regime. And what horrible fate awaits Jo at the hands of her captors? She’s offered grapes and wine and the promise of a feast. The Daleks have really lost their touch…