The Impossible Planet

An outpost on a rocky world, in stasis around a black hole, the TARDIS sets down inside it (the outpost), the Doctor and Rose patrol. Not long after they encounter all the outpost's personnel (including some Ood ones) but an earthquake causes problems, sends the TARDIS down to hell. Buried deep there is a power source (that's why humans are here), it's maintaining suspension, curtailing all cascading, to the event horizon. Soon the writings on the wall (amongst other things) for some, the Doctor must descend (with Ida), to the caverns of the underworld, in limbo there is no end (or is there?).