Doctor: David Tennant (Tenth Doctor)
Companion: Catherine Tate (Donna Noble)
Billie Piper – Rose Tyler
Lesley Sharp – Sky Silvestry
Rakie Ayola – Hostess
David Troughton – Professor Hobbes
Ayesha Antoine – Dee Dee Blasco
Lindsey Coulson – Val Cane
Daniel Ryan – Biff Cane
Colin Morgan – Jethro Cane
Tony Bluto – Driver Joe
Duane Henry – Mechanic Claude
Directed by Alice Troughton
Written by Russell T Davies
Script editor Helen Raynor
Produced by Phil Collinson
Executive producer(s) Russell T Davies
Incidental music composer Murray Gold
Production code 4.8
Series Series 4
Length 45 minutes
Originally broadcast 14 June 2008
The Doctor and Donna visit the resort planet Midnight, the surface of which is bathed in lethal galvanic radiation from its xtonic star. The Doctor plans to take a shuttle to visit a waterfall made of sapphires, but is unable to convince Donna to leave the comfort of the local spa. He decides to take the trip by himself and sets off. Upon departure of the shuttle, the hostess starts a cacophony of on board entertainment which the Doctor disables with his sonic screwdriver. This forces the other passengers to engage each other in conversation as they travel.
The shuttle stops unexpectedly mid-route, and the pilot reassures everyone that they are fine. The Doctor uses his psychic paper to get himself into the cockpit, where the driver and mechanic report that the engines seem to be operating normally but they are not moving. The Doctor encourages them to open the cockpit shields to see out, and before the radiation forces them to close the shields the mechanic swears that he saw something moving towards them. The driver sends out a distress call and a rescue shuttle is dispatched but will take some time to arrive. Soon, a rhythmic knocking starts on the hull of the shuttle. The knocking seems to be mimicking the sounds the passengers make on the walls. The knocking moves around the hull to where a passenger named Sky is cowering, then the shuttle is rocked and the lights fail. The hostess opens the cockpit doors only to find the cockpit has been torn off the shuttle.
Sky begins behaving oddly and the Doctor attempts to talk with her but she simply repeats everything he says, including the square root of pi to thirty decimal places. As the passengers huddle and discuss things, the delay in Sky's repetition shortens until she is saying things at exactly the same time as the others say them. The Doctor tests Sky by speaking quickly and randomly to see if she keeps up, which she does perfectly. The passengers become afraid and believe Sky is possessed, and begin plotting to murder her by shoving her off the shuttle. The Doctor steps in and tries to calm the passengers, taking it upon himself to talk to Sky, but they grow suspicious of the Doctor as well. The Doctor realises that Sky is now repeating only his words, increasing the suspicions of him even further. The Doctor makes one last attempt to communicate, offering to help the entity find what it needs without hurting anyone. The other passengers then observe Sky starting her sentences before the Doctor, who repeats them after a short delay. They suspect that whatever had possessed Sky has now moved on to the Doctor.
Sky attempts to convince the others that she's back to normal. She blames the Doctor for what is happening and encourages them to throw him off the shuttle to save themselves. The Doctor is visibly disturbed as he is frozen, tears brimming and struggling for control, but compelled to keep repeating everything Sky says. The passengers begin hauling the Doctor off the shuttle. The hostess and Dee Dee begin to suspect that Sky is still possessed and that she is attempting to trick them. The hostess becomes convinced when Sky uses words and phrases the Doctor used at the beginning of the trip. The hostess surprises Sky by grabbing her, and then sacrifices herself to drag them both off the shuttle and into the lethal radiation. With Sky dead, the Doctor returns to normal. The other passengers reflect on how they acted, and the rescue shuttle arrives to collect them. They note that none of them knew the name of the hostess.
Back at the spa, the Doctor reunites with Donna and gives her a prolonged hug. After they converse about what happened on the bus, Donna prompts the Doctor to tell the Leisure Palace Company to leave Midnight; the entity may still be alive or there may be more than one of them out there. Donna can't fathom what the Doctor would be like without a voice. The Doctor tells her, "Molto bene", in relief. Donna copies him. Disturbed, the Doctor tells Donna not to do that, then looks away, clearly still haunted by these events.