Steed wants Mrs. Gale to impersonate Hilda Stern, a recently arrested assassin about to be used by the trans-national crime syndicate Intercrime. Things go swimmingly, until the real Hilda Stern breaks out of Holloway and confronts the imposter.

All the occupants of a rest home, Adelphi Park, are multi-millionaires. And most of them are refusing to see anyone, including Professor Renter who was due to fly to America with Steed to show off his latest invention. His wife is unable or unwilling to help and, curiously, the neighbour, Madden, another millionaire, is missing.