The TARDIS materialises on the runway of Gatwick Airport, where Polly witnesses a murder only to be kidnapped before she can report it.

The Doctor, Jamie and Sam manage to convince Crossland to trust them and he persuades the Commandant to let them continue their investigation.

Jamie finds himself aboard the Chameleons' satellite and meets their Director while the Doctor forces the Chameleon Meadows to tell him the aliens' plans.

The Doctor and Pinto are captured by the Chameleons but the Doctor manages to use their dependence on their human originals to create dissent in their ranks.