The Doctor and Jamie return to the canoe and report to UNIT. The Doctor realizes that the Cybermen's spaceships are homing on signals from Earth and wonders about them taking control of people who go into the IE complex.
General Rutlidge tells the Brigadier he will not support any action against IE. The Brigadier threatens to get Geneva to over-ride Rutlidge. Rutlidge then contacts Vaughn for more instructions. When Rutlidge becomes confused, Vaughn orders him to report to IE.
Rutlidge tells Vaughn that it will be one or two days before UNIT can act. This is enough time for Vaughn but he needs to test Dr. Watkins' machine. The Cyber-Director confirms the advance of the invasion plans.
Packer keeps reviving Cybermen and has them muster in the sewers. The Brigadier worries that Geneva will not believe his invasion claims without proof. The Doctor starts inspecting the IE electronic components.
Vaughn has his men partially revive a Cyberman and connects Watkins' machine to it. He introduces fear to its circuits and the Cyberman struggles and screams. It staggers into the sewer, deranged and damaged.
Isobel suggests they go into the sewers and get pictures of the Cybermen as proof of the invasion. The Brigadier decides to send his own team and his sexist attitude annoys the young lady. Zoe and Isobel decide to investigate on their own.
The Doctor finds surplus circuits in all of the IE equipment.
The Cyber-Director tells Vaughn they will supress all of the humans, convert those who are suitable and slaughter the rest. But Vaughn demands control of Earth. They Cyber-Director requires complete conversion but Vaughn refuses – his body may be cybernetic but his mind will stay human. The Cybermen agree. Vaughn tells Packard he knows the Cybermen will betray him.
The Brigadier and the Doctor find out that the young people have gone to London to get pictures of the Cybermen. The Brigadier angrily demands their return but they are already descending into the tunnel.
They see a shape in the distance and the wounded Cyberman struggles into view. As Isobel snaps pictures of it, a constable follows them into the sewer. He is cornered by two Cybermen and killed. Jamie, Zoe and Isobel are now trapped…