PREVIOUSLY: Review: 'Doctor Who' Season 9 Episode 2, 'The Witch's Familiar,' Plays With Mercy Who Ya Gonna Call? After the high-octane opening episodes, "Doctor Who" drops instantly into a more muted, quietly threatening mood with the Toby Whithouse-penned "Under The Lake." For an episode that includes ghosts, a spaceship and a nuclear reactor, it feels pared down rather than a checklist of cool stuff, foreboding rather than dramatic, and all the better for it.