In the summer of 1966, thousands of young people are taking their holidays with Chameleon Tours. And not one of them is coming back. When the TARDIS lands at Gatwick Airport the Doctor is drawn into a web of intrigue and deception. To add to his troubles, Polly mysteriously vanishes. Or does she? The girl at the Chameleon Tours desk looks like Polly, and even sounds like her, but she claims she comes from Zurich. Who is she really? Who is behind these abductions? And for what sinister purpose? Soon the Doctor and Jamie must face a desperate group of faceless aliens - the deadly Chameleons…