When attractive American Jacqueline Kirby is invited to an English country mansion for a weekend costume affair, she expects only one mystery. Since the hosts and guests are all fanatic devotees of King Richard III, they hope to clear his name of the 500-year-old accusation that he killed the little princes in the Tower of London. Jacqueline puts all her observations together for a dazzling solution that will surprise even the most attentive listener.