Swinging playboy Grand Duke Nicholas Goduno, a direct descendent of the Romanov family who were overthrown in the Russian Revolution of 1917, learns that his family's crown jewels will be exhibited at a London museum and plots to steal them. To this end, he gathers a crew of beautiful but dangerous women, led by Bridget Rafferty, to assist in his plot against Popov, the Soviet functionary in charge of the exhibit.
| Actor | Role |
|---|---|
 Marcello MastroianniGrand Duke Nicholas Wladimirovitch Goduno | Grand Duke Nicholas Wladimirovitch Goduno |
 Rita TushinghamBridget Rafferty | Bridget Rafferty |
 Elaine TaylorVictoria | Victoria |
 Margaret BlyeHoney | Honey |
 Warren MitchellPopov | Popov |
 Leonard RossiterInspector Dudley | Inspector Dudley |
 Bill FraserBookseller | Bookseller |
 Bryan PringlePolice Sergeant | Police Sergeant |
 Francesca TuJeanne Silkingers | Jeanne Silkingers |
 David HorneDuke of Windemere | Duke of Windemere |
 Charles Lloyd PackButler | Butler |
 Anne BlakeNashka | Nashka |
 David WebbNot listed | Not listed |
| JJuba KennerleyCasino Patron (uncredited) | Casino Patron (uncredited) |
 Ian TriggerPopov's assistant (uncredited) | Popov's assistant (uncredited) |
 Norman Mitchell(uncredited) | (uncredited) |
 Nora NicholsonAnastasia Petrovna | Anastasia Petrovna |
 Rosalind KnightMuseum Visitor in Pink Dress (uncredited) | Museum Visitor in Pink Dress (uncredited) |