Super-agent John Steed goes to Hong Kong to pick up a suitcase filled with valuable papers. Steed is in Hong Kong less than an hour when he's knocked unconscious, and the contents of the case are mysteriously switched — to a huge sum of money!

Back goes Steed to London. There, he and Tara King set to work baiting a trap for the owners of the fantastic fortune foisted off on him — a trap that almost snaps shut on The Avengers themselves!