The Doctor is a Time Lord: a 900 year old alien with 2 hearts, part of a gifted civilization who mastered time travel. The Doctor saves planets for a living—more of a hobby actually, and the Doctor's very, very good at it.
The Le Verrier space station fell silent only a day ago. No-one really knows what happened. However, some footage of the attempted rescue mission was found. The station appears empty, except for two nosy time travellers: the Doctor and Clara.
