TEXT: Recap of Episode 4. OPENING CREDITS DONNA: He's gonna choke! Doctor! DOCTOR: It won't open! Sylvia rushes to the car with an axe and smashes the windscreen. SYLVIA: Well, don't just stand there! Get him out! UNIT OFFICER: All soldiers to a door! Make the factory secure and take positions on the ground floor! COLONEL MACE: Wicowsky, take the soldiers into the factory! Make the area secure. Seal off doors and windows. Soldiers are pushing the cars out of the factory. SOLDIER: We've tried everything, it just won't stop! Colonel Mace goes into the UNIT field base. COLONEL MACE: What have we got? CAPTAIN PRICE: ATMOS is running wild, sir. It can't be stopped, it's everywhere. The whole planet. The Martha clone enters the UNIT base and uses Martha's level 1 security clearance to get into the NATO defence system. WILF: Thanks! DONNA: I can't believe you've got an axe! SYLVIA: Burglars! DOCTOR: Get inside the house. Just try and close off the doors and windows. Ross pulls up in a black cab. ROSS: Doctor! This is all I could find that hasn't got ATMOS. The Doctor runs to the cab, shouting back to Donna who is still with Wilf and Sylvia. DOCTOR: Donna, you coming? DONNA: Yeah! SYLVIA: Donna! Don't go! Look what happens every time that Doctor appears! Stay with us, please. WILF: You go my darling! SYLVIA: Dad! WILF: Don't listen to her! You go with the Doctor! That's my girl!... Donna gets into the cab, though feeling guilty to leave her family. WILF: Bye! The Martha clone downloads the security protocols to her PDA. COMMANDER SKORR: Success, the operative has the necessary information. GENERAL STAAL: Good work for a female.
SUMMARY:
Sylvia frees Wilfred. The Doctor and Donna return to the ATMOS factory, where the Doctor warns UNIT not to engage the Sontarans. The Doctor tells Donna to stay in the TARDIS, but the Sontarans teleport the TARDIS aboard their ship. The Sontarans defeat UNIT at the factory and take it over. UNIT manages a counterattack. Finding the TARDIS missing, the Doctor tells Donna to re-engage the teleport pods. The Doctor enters the factory and awakens the real Martha. The Doctor learns from Martha's clone that the gas is being used to convert Earth into a breeding world for the Sontarans. The Doctor tells Donna how to use the pods and teleport the TARDIS to Earth. The Doctor constructs an atmospheric converter at Rattigan's academy, which harmlessly ignites the gas and allows the humans to breathe. He calibrates the converter so it can ignite the Sontarans on board their ship, and teleports on board. The Doctor offers Staal the chance to retreat, but Staal encourages him to destroy them. Rattigan switches places with the Doctor, sacrificing himself to destroy the Sontarans. Martha is trapped on the TARDIS when it takes flight on its own.