Or, to give it its proper title, The Two Point One Doctors. Hartnell’s ill health meant that the First Doctor’s role was reduced to a couple of cameo slots where he imparts advice “trapped in time” on a viewscreen.
The standout feature of this story is the interplay between the Doctors, alternately bickering, helping each other, and generally gently winding each other up. It’s pretty much what you’d expect, and that’s no bad thing. Pertwee’s costume has evolved into something less silly and the character generally seems a lot more mature, and Troughton’s performance is as much of a joy to watch as I’d expected. The whole thing is played for laughs, which is a long-overdue shot in the arm for the show.
Downsides are Jo Grant being as pointless as ever, and an otherwise robust plot is marred with far too much running and SHOUTING. Which is a shame, cos there’s a lot going on. We’ve got Omega, an old Time Lord who created the power source which made time travel possible; the Time Lords in some sort of mission control back at Gallifey; and a game-changer ending. Omega in particular, driven spare by being stuck in a black hole on his own for yonks, is full of RAGE and SHOUTS a lot. He wants the Doctors to keep him company, a prospect not akin to spending an eternity in a cupboard with Brian Blessed. “WOULD YOU LIKE A CUP OF TEA?” he’d ask, probably.
So yeah. A Third Doctor story that’s well worth watching, largely because it’s got the Second Doctor in it.