Parts: 1 (45-minute)
Writer: Chris Chibnall
Airdates: 19 May 2007
Production Code: n/a

Doctor: tenth
Companion: Martha

Story: The Doctor and Martha are soon separated from the TARDIS when it arrives onboard the S. S. Pentallian a mere 42 minutes before the ship is due to plunge into the sun of the Torajii system. Galvanized into action, they try to help the crew repair the damaged systems in time, as they learn that it wasn't just an ordinary systems failure that caused the ship to veer out of control - it was sabotage, apparently perpetrated by a crewmember named Korwin, the husband of the captain. In the ship's medical bay, Korwin lies writhing, screaming that he's burning up from the inside, and his wife knows he would never have endangered the crew - so what happened to him?

As the clock ticks slowly down to impact, something seems to possess Korwin, causing him to go on a murderous rampage and incinerating the crew one-by-one... with just a look from his blazing eyes. With an implacable killer stalking the corridors, and the ship's controls far out of reach, the Doctor and Martha begin to fear that this time, they have no chance of making it out alive.