Lester recovers consciousness and stops Harry from removing the harness just in time. Harry explains where Sarah Jane is and what the plan is. With nine minutes left, the Doctor has Stevenson continue on since the Cybermen can't differentiate the bomb signals. They grab some gold and prepare to attack the Cybermen.
Tyrum tells Vorus he'll be tried for treason if they all survive, but Vorus is defiant and claims he is a patriot. The militia report they can no longer attack the Cybermen and Tyrum goes to rally them. The Doctor, Harry, and Lester slip up behind the Cybermen and try to crush the gold into their chest units. The Cybermen easily overpower Harry and the Doctor, who run for it. Lester leaps down and releases his bomb, killing himself and the two Cybermen.
The Doctor finds the detonator, which is still intact. The Cyberleader notes they have lost contact and prepares to activate the signal manually, and Sarah Jane fruitlessly intervenes. The Cyberleader activates the detonator…but the Doctor has already deactivated it and the harnesses.
Sarah Jane inadvertently reveals Kellman led them into a trap and the Vogans are preparing to launch a rocket. The Cyberleader concludes there is a malfunction because they haven't already launched.
The Doctor meets with Tyrum and Vorus and it's revealed the bomb is ready for launch. The Doctor suggests they give him fifteen minutes to deal with the Cybermen. Tyrum agrees and also gives the Doctor the gold dust he asks for. A disgruntled Vorus is unhappy he has to wait.
The Doctor transmats up to Voga while the Cybermen load Nerva with Cyberbombs and prepare to launch it at Voga, destroying it. They tie up Sarah Jane and go to their ship. The Doctor arrives and frees her, and takes the Cybermat and loads it with gold dust. With seven minutes left, Vorus gets increasingly impatient and boasts of how the people will beg him to lead them. Harry returns with Stevenson with five minutes left.
The Doctor finishes modifying the Cybermat as the Cybermen start Nerva's engine and discover Sarah Jane is missing. He sends his Cybermen to search the Beacon, and one of them enters the room where the Doctor is. He directs the Cybermat at it to inject gold dust, killing it.
With two minutes left, they head fro the control room as the Beacon starts to fall towards Voga. Stevenson and Harry try to stop Vorus from launching, and Tyrum shoots him down…a second too late. As the missile launches, the Doctor unleashes his "pet" Cybermat on one of the remaining Cybermen but the other ones overwhelm the Doctor and Sarah Jane. The Cyberleader has them tied up and leaves them to witness the destruction of Voga first-hand.
The Doctor gets loose and calls down to tell them to aim the missile at the Cybership, but no one knows how to change the controls. The Doctor talks Stevenson through the procedure to direct the missile away from Nerva and toward the Cybership. Unfortunately the Cybermen have locked the controls and it continues on course for Voga.
The Cyberleader orders evasive action…too late. The Cybership is destroyed. The Doctor manages to override Nerva's flight path via the secondary controls and they pull away just in time. Nerva returns back into orbit and the TARDIS arrives. Harry transmats up as the Doctor reveals the Brigadier has used a space-time telegraph system to call for help, and they take off for Earth.