Parts: 6
Writers: David Ellis and Malcolm Hulke
Airdates: 8 April 1967 - 13 May 1967
Production Code: KK

Doctor: second
Companions: Ben, Polly, Jamie

Creature Feature: Chameleons

Story: The TARDIS materializes smack-dab in the middle of one of the runways at Gatwick Airport, much to the consternation of traffic control, who quickly have it carted away while the TARDIS crew are occupied being pursued by the police. Polly, attempting to shake off her pursuer, slips into one of the airport hangars, where she bears witness to a murder - but no ordinary murderer. The killer, Polly is sure, used some kind of ray gun.

Once the police search has cooled down, Polly leads the Doctor and Jamie back to the Chameleon Tours hangar, where the Doctor confirms that the man was killed using extraterrestrial technology. But unbeknownst to the TARDIS crew, they are being monitored...and Polly's vehement admission that she can recognize the murderer marks her for elimination. As they leave to report the murder, Polly is snatched away from under the Doctor and Jamie's noses. While the officials refuse to believe the Doctor and Jamie's wild-sounding story, and the telltale body goes missing, Polly reappears...claiming to be Michelle Leuppi from Zurich, who has never met the Doctor and Jamie before in her life.

When the Doctor finds an advertisement for Chameleon Youth Tours in the newspaper, his suspicions begin to form. It seems that the passengers on these youth tours never arrive at their destination, although postcards are mailed back to their families at home, and Chameleon Tours seems determined to cover the situation up...even if the murder is the only way. But what is happening to their young charges, and what is their ultimate aim? The clock is ticking down, for while the Doctor and Jamie try to solve the mystery, Chameleon Tours has captured the helpless Ben and Polly...