Aired Friday, July 11, 2008 on Sci Fi.

Guest stars: Lesley Sharp (Sky Silvestry) was in The Full Monty and was in The Second Coming with Christopher Eccleston. David Troughton (Professor Hobbes) is the son of Second Doctor Patrick Troughton and was King Peladon in "The Curse of Peladon" 36 years ago. Ayesha Antoine (Dee Dee Blasco) was a regular on Grange Hill. Colin Morgan (Jethro Cane) will be playing the title role in Merlin this fall. Billie Piper once again gets guest star billing for a brief appearance on a monitor.

Creators: Written by Russell T. Davies. Directed by Alice Troughton (no relation).

The episode: This is a bottle show, most of the episode taking place inside the passenger compartment of the Crusader 50 shuttlebus. The Doctor and Donna are on vacation on the planet Midnight, where the landscape is made of diamonds but the sunlight is lethal to all life. Leaving Donna to relax in the leisure hive – I mean, palace – the Doctor takes a four-hour trip to see the fantastic sapphire waterfall. (Catherine Tate got a bit of a holiday herself and only appears at the beginning and end of the episode. There's no TARDIS in this episode either, apparently for the first time since "Genesis of the Daleks" in 1975.) Unfortunately a mysterious entity invades the shuttle, infesting the businesswoman Sky and setting the passengers against each other as their fear escalates. The Doctor is increasingly unnerved himself as the possessed, motionless Sky starts repeating everything the others say – first after they say it, then at the same time. The Doctor realizes the entity is learning, but his efforts to stop the others from ejecting her into the lethal sunlight only brings suspicion on himself – which seems confirmed when Sky seems to return to normal and the Doctor, now motionless as she was, begins repeating her. The others assume this means the entity transferred to him, and, goaded by Sky, drag the Doctor toward the airlock. At the last minute the hostess (Rakie Ayola), realizing the entity is still in Sky and has stolen the Doctor's voice (Sky says allons-y, which the hostess heard the Doctor say at the start of the trip), pulls Sky to the airlock and sacrifices herself along with the entity to free the Doctor and the rest. As rescue finally arrives, the Doctor and the chagrined passengers realize they didn't know the hostess's name.

Afterthoughts: Usually the Doctor is able to handle angry clusters of humans – I was thinking of the "Fingers on lips!" moment in "Fear Her" – so it's arresting to see him unable to gain control of a situation, with both the potential victims and the threat getting quickly out of hand, and the Doctor's air of mystery being turned against him. After a lot of stories in which the Doctor has been very larger than life, "Midnight" was a very necessary revisiting of the Doctor's fallibility. Not coincidentally, he's alone, deprived of the softening his companions bring to his alienness. The rest of the cast was strong, and a nice mix; the preview of young Colin Morgan, soon to have the lead in his own series, suggests he's still a bit green but can stand out in a group (his Jethro moves from confidence to uncertainty, the opposite direction from his increasingly paranoid fellow passengers). The end tag, showing the Doctor unnerved by the whole thing as he recounts it to Donna, was a nice touch. Verdict: Molto bene.

Next week: Rose Tyler (Billie Piper) finally returns in the flesh, teaming up with Donna to undo an alternate timeline where everything's wrong.