10 Greatest Classic Doctor Who Stories
3. Inferno
As Peter Capaldi's hiatus year of 2016 proved, the world can be an incredibly dark and dystopian place when the Doctor isn't around. Inferno explores this central idea, in one of Doctor Who's rare alternate reality episodes.
Inferno asks the question of "what happens when the Doctor can't save the day?" but gets to have its cake and eat it by having the Doctor save the day. Doctor Who had long established that the Doctor can't just pop in the TARDIS and have another go if he fails. By stranding the Doctor in a parallel dimension, Inferno found a creative workaround to give the Third Doctor a second chance.
It also gives Nicholas Courtney, Caroline John, and John Levene the chance to mix things up by playing their fascist counterparts. While that's become something of a trope since Star Trek's Mirror Universe episodes, it was still a relatively fresh concept in 1970.
Inferno is an apocalyptic epic that also works as the Third Doctor's Christmas Carol. He starts as Ebenezer Scrooge, grumpy and unwilling to live among humans. Then, having seen just how bad things could be, he becomes the more charming Third Doctor we know and love.