"The Well" Is a Surprise Sequel to An All-Time Great 'Doctor Who' Episode

When a franchise has been around as long as Doctor Who has, it's inevitable that it's going to revisit some of the same stories over time. Most often, that's reflected in repeated encounters with the Time Lord's most famous enemies: Daleks, Cybermen, and the Master. But sometimes, everyday adventures are more directly connected to those that have come before them.

Last season's "The Legend of Ruby Sunday"/"Empire of Death" two-parter was a stealth sequel to the classic 1975 Fourth Doctor episode, "The Pyramids of Mars." The 60th Anniversary installment, "The Giggle," was a follow-up to 1966's "The Celestial Toymaker," a First Doctor story that aired over 50 years ago. During the Steven Moffat era, "World Enough & Time" presented an alternate origin story for the 1966 serial that introduced the Mondasian Cybermen. And "The Zygon Invasion/The Zygon Inversion" picked up on a subplot that initially began in the 50th Anniversary episode "The Day of the Doctor."

But even among those adventures, "The Well" stands out. The hour is creepy enough in its own right; a base-under-siege-style episode that features mysterious deaths, an inexplicable unseen enemy, a dilapidated mining facility, and a hole that extends so far into the planet's center that not even light can reach it.