2. The Power of the Daleks (Second Doctor, Season 4 - Story 30)
Except, it's gone too. Perhaps the universe is playing a massive joke on fans of Doctor Who, but the entire next serial - Hartnell's regeneration, Troughton's debut as the Doctor - was purged from the BBC Archives. This episode brings the newly regenerated Doctor and his companions out of the frying pan... and right back into the fire, as they end up on a human colony on the planet Vulcan. The usual intrigue and mystery, leading up to intense action, is present here: the Doctor, still a bit out of it from his transformation, assumes the identity of a dead man called the examiner by members of the colony. When the real examiner is found, the Doctor - and several other people - are accused of conspiracy and murder. Meanwhile, a colony scientist discovers a Dalek capsule - with an apparently dead Dalek inside. The Dalek multiplies, soon creating enough to easily overtake the base; only after a lengthy and costly battle, and the Doctor cutting off the Daleks' power source, are the humans able to push the horde back.