On learning his wife has given birth to a son, the Russian Grand Duke wagers the last of the Imperial jewels. Some decades later, the son, played by Marcello Mastroianni, sees them as part of an exhibition at an English museum. When he recovers, he assembles a team of lady burglars to steal them.
Mastroianni should be having a lot of fun, playing his role and all his ancestors, and with the women, including Rita Tushingham, Elaine Taylor, Margaret Blye, Francesca Tu, and the Karlin Triplets. He seems at sea speaking English, with none of the comic charm he typically offers in Italian movies. The pacing seems erratic, as if large swaths have been cut out in an effort to transmute smuttiness into ribaldry.
Perhaps it is the lack of anything in the way of character for any of the performers, save for Miss Tushingham, Nora Nicholson as an elderly Grand Duchess, and David Horne in his last screen appearance, as a bleary-eyed English aristocrat. In any case, it's not much good.