The supporting cast of "The Beast Below" consists of Sophie Okonedo as Liz 10, Terrence Hardiman as Hawthorne, and Hannah Sharp as Mandy. Sharp impresses the most, given her age; Hardiman's role as the mysterious man behind the screens is very evocative of the villains of classic Doctor Who; and Okonedo is a bit of a letdown, given how much screentime she had, and how important her character was. The accent and dialect didn't help ("I'm the bloody queen, mate!"); her anger at being deceived, and sadness when she recounts the horror that led to the formation of Starship U.K., never come across convincingly.

Large parts of "The Beast Below" feel recycled: the premise of the episode bears resemblances to the 1970 story The Ark in Space, where the Fourth Doctor (Tom Baker) encountered space-based human colonies after solar flares made the Earth uninhabitable; humans in space being watched by someone - or something - living at the extreme end of the structure echoes 2005's "The Long Game"; and the final reveal is too similar to "Encounter at Farpoint" (1987, Star Trek: The Next Generation) to be comfortable. There might even be a touch of "Planet of the Ood" (2008). Maybe that's why the episode left me feeling a little underwhelmed - not only is it nothing new, it lacks a new take on something old. It has good moments and good characters, but they fail to add up to a satisfying conclusion. Throwaway lines ("Half-human, half-Smiler") and faulty logic (if the Star Whale came to help, why was it enslaved and tortured?) hold the episode back from reaching any significant heights.

Of course, these are but still early days in the series, and "The Beast Below" has the unenviable honor of being sandwiched between high-profile episodes: on the one side, it follows the series premier "The Eleventh Hour"; and on the other, it precedes the "Victory of the Daleks" and the return of the Weeping Angels in "The Time of Angels" & "Flesh and Stone". There are moments in "The Beast Below" that lay the seeds for important plot points in the series to come - we see the crack from "The Eleventh Hour", and there's a mystery surrounding Amy's marital status - so the episode won't be entirely forgotten. But this was one episode of Doctor Who that was merely "alright". "Good" in places and "not bad" in others.