The Trap is the 13th produced, and the 7th broadcast, episode of the British television series Captain Scarlet and the Mysterons.
A World Air Force plane carrying Commodore Goddard and his right-hand man, Captain Holt - being escorted by Melody Angel - is struck by lightning and crashes. It is soon reconstructed by the Mysterons, who broadcast its current threat: that they aim to kill all ten of the world's top air-chiefs, who comprise the WAF's executive Supreme Command.
The Supreme Command - who want to discuss a plan to dissolve the "war of nerves" between Earth and the Mysterons - are convening an International Air Conference at the loneliest location in Europe: Glen Garry Castle, in Scotland.
This is, however, unknown to Colonel White, who's awaiting word from Captain Scarlet that the castle's security is up and approved. After Symphony Angel brings the delegates to the castle to start the conference, she and Scarlet are taken prisoner...
Now - with the air-chiefs lacking any advance-warning, and in perfect firing positions to be massacred by the Mysteronized Goddard and his personal aide - will Colonel White realise in time that something is wrong? And, can Captain Scarlet yet save the day?
- The right-hand half of the Glengarry Castle miniature - which can be seem in establishing shots of the the location, - previously appeared as Glen Garrick Castle in the Thunderbirds episode 30 Minutes After Noon. It was originally produced for the Stingray episode Loch Ness Monster, where it appeared as Castle McGregor.
- Additionally, some of the furnishings inside the castle, such as the puppet-sized wooden chairs (the cushions on which were re-upholstered for The Trap), previously appeared in both of the aforementioned series.
- Bob Bell contributed a painting to this episode - specifically a painting of an 18th-century lady in a rococo dress. This appeared in the main hall of Glengarry Castle, as well as on the wall of Captain Scarlet's bedroom at said castle. It originally featured in Thunderbirds, in two places—the British Security Office seen in 30 Minutes After Noon, and the lounge of Creighton-Ward Mansion.
- The puppet playing Morton was modelled on actor Robert Mitchum.
- When the Distillery Attendant says "Identification please." he is voiced by Martin King. But when he says "Right away, sir." he is voiced by Jeremy Wilkin.