When the world's greatest jewel thief, Sir John Locksley (Rex Harrison), realizes he hasn't much longer to live, he decides to bequeath his prize possession, the Shalimar ruby, to a worthy candidate. To find the lucky recipient, he invites several rival thieves to his island estate and offers the priceless gem to whoever can successfully steal it. Unfortunately, the losers face certain death. John Saxon and Sylvia Miles co-star.