AllMovie

Government scientists develop a knockout gas, designed to peacefully quell terrorist uprisings. The gas, and its antidote, inevitably fall into the Wrong Hands, those hands belonging to a gang of crooks who plan to send all of London off to slumberland so that they can embark upon a wholesale crime spree. To prevent this, the New Avengers once again go undercover--with Purdey (Joanna Lumley) posing as a department store window mannequin.