The Hour That Never Was
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"The Hour That Never Was" is an episode of the television show The Avengers. The first two-thirds of the episode feature John Steed and Emma Peel wandering around a deserted RAF aerodrome, given the fictitious name of Hamelin, where the fictitious Squadron 462 is based. Steed tells of his exploits in the RAF during the Second World War; he has taken Mrs Peel there for his reunion with fellow RAF officers prior to their transferral to other bases around the globe with the dissolution of this airbase.
Although shot on location, the episode tries to be mysterious -- with all that walking around, and each base clock stopped at 11 a.m. -- rather than dramatic. There is a fight in the last five minutes of the episode, however.
It is the airbase's dentist who discovered that the sound of his drill produced ultrasonic sound waves which, when amplified over the base's public address system, caused the other men to fall unconscious. His scheme was to brainwash all of them so that they would be under his control, which he would as is common "sell to the highest bidder". The gimmick would be that they would be posted to all sorts of places other than a backwoods base in Britain, and so be privy to secrets that foreign powers would be more interested in.
One point that is not literally mentioned is that the guard dog who, in running across the road in front of Steed's Bentley at the start of the episode causes him to crash, did so because he was unnerved by the ultrasound which a dog could hear better than humans.
The bit of bondage in this episode is that Emma Peel is tied to the dentist's chair.