The Doctor and the miners fight to reclaim Peladon from the Ice Warriors.
The Doctor gains control of the mechanism creating the Aggedor apparitions and uses it against the Ice Warriors. Only Sskel survives and returns to Azaxyr. The Doctor sends Gebek back to his miners with a plan – he’ll control the Aggedor apparitions to get the miners back on side.
Eckersley communicates with the Doctor. He turns the security system on at the low level, warning the Doctor to surrender. The Doctor sends Sarah out to warn Gebek. Azaxyr prepares his warriors to attack the miners. An Ice Warrior approaches a group of miners, but Aggador appears and kills him. Eckersley turns up the intensity on the security system.
Azaxyr prepares an ambush for the miners and guards who are approaching the citadel.
The Doctor sends the Aggador apparitions to the Citadel, where it kills more Ice Warriors. The miners and guards head for the throne room. The Doctor collapses, finally overcome by the security system. Sarah finds a gun on a dead Pel and threatens Eckersley to make him turn off the security system. He shows her on the monitor that the Doctor is already dead, but when she looks, he takes the gun from her. He locks her in the communication room.
The miners and guards storm the throne room, where Azaxyr holds his weapon on Queen Thalira. The Pels drop their weapons, but attack the much slower Ice Warriors instead; in the resulting melee, Azaxyr and his men are all killed.
Sarah is freed from the communication room by Alpha Centauri and heads for the refinery and the seemingly dead Doctor.
Eckersley, his allies now dead, heads for the throne room and takes Thalira hostage. They head through the tunnels.
Sarah learns that the Doctor is not dead after all; he had placed himself in sensory withdrawal to avoid the effects of Eckersley’s security system. The miners and guards learn that Queen Thalira has been captured and inform the Doctor. He decides to get Aggedor’s help.
That “help” is provided by the real Aggedor, who the Doctor has used to track down the Queen by her scent. Aggedor attacks and kills Eckersley, but is himself killed in the process.
As everyone recovers in the throne room, Alpha Centauri excitedly announces that Galaxy Five has sued for peace, now that their gambit on Peladon has been defeated. Thalira and her new Chancellor – Gebek – commit themselves to a new beginning for Peladon, while the Doctor and Sarah slip away to the TARDIS.