The face disappears before Sarah sees it and she lets the Doctor out. Styggron then contacts Crayford, who tells him the Doctor and Sarah are space travellers.
While hiding from the guards, Sarah tells the Doctor that Crayford was killed in a deep-space accident several year previously. They meet Benton in the complex, who prepares to kill them on Crayford's orders. But Styggron forces Crayford to order the travellers captured and they escape. All of the UNIT forces, including Harry Sullivan, are sent to search for them. The Doctor wonders if something returned with Crayford and is now controlling the soldiers and villagers.
As they flee into the woods, Sarah hurts her ankle. The Doctor hides her in a tree while he leads the tracker dogs away. He hides in a river to shake the pursuit but Sarah is caught when she climbs out of the tree. Styggron then orders Crayford to track but not capture the Doctor.
Sarah finds herself in a theatre with Harry Sullivan operating a complex device. She is painfully analyzed by the hideous Stryggron.
The Doctor returns to the pub. He notices the odd behaviour of the landlord, the completely new darts board, a calendar with the same date and other little oddities. He is carefully watched by Styggron and Chedaki, two Kraals. They want to see if their techniques will work in other circumstances. Chedaki, however, feels the Doctor is a threat to their plans.
The pub receives a call from Sarah, who tells the Doctor to meet her in the village store. The phone then goes dead again.
Chedaki worries that the Doctor will reprogram the Kraal's androids to attack Kraals. Styggron decides to make another android from Crayford, one hostile to Kraals.
The Doctor meets Sarah, but his suspicions are aroused by her uncharacteristic behavior. She tells him Crayford and whatever forces he is allied with are copying people. The Doctor, however, thinks Sarah was let go so their intelligence could be tested. He thinks Stryggron is using the duplicates to create a bridgehead for the invasion of Earth. He decides to return to the TARDIS and radio for help.
Styggron copies Crayford into a new android, which instantly attacks him. But Styggron has a new weapon he uses to destroy the android.
The Doctor and Sarah return to the clearing where the TARDIS has disappeared. The Doctor realizes that Sarah put the key in and cancelled the pause control, allowing the TARDIS to continue to Earth. They are not really on Earth, but a different planet. The entire village is a fake.
When he tells Sarah that she is also a fake, she pulls a gun on him. The Doctor knocks it away and Sarah tumbles to the ground. Her face falls off toe reveal the inner workings of an android…