Suspicion is cast on the neighbour who makes movie props and whom the Colonel dislikes. Blake has been dating another platinum blonde, but his girlfriend is still alive. The autopsy reveals the woman was drugged, died between 10 pm and 12 midnight. Despite her appearance, she was still a virgin. She is identified as Ruby Keene, a dancer at the Majestic Hotel. A fellow dancer, Josie, and had had Ruby fill in for her as an exhibition dancer with Raymond Starr, the hotel's tennis star and dance instructor. However, when Ruby went missing Josie still had to perform, despite her ankle.
Conway Jefferson, a hotel guest who had become fond of Ruby, phoned the police when she went missing. Several years before, Conway had lost his wife, son and daughter in an airplane crash in which he had also lost his legs. He is now accompanied by his daughter's widower, Mark, and his son's widow, Adelaide, who are now his heirs. Conway planned to adopt Ruby and leave her as sole heir to his fortune, which would leave Mark and Adelaide with nothing. However, they were accounted for, playing bridge in the hotel ballroom with Conway and Josie. George Bartlett was Ruby's last dance partner that night.
The police suspect that Ruby sneaked off to meet someone who strangled her. Bartlett's car is found with the corpse of another girl, Pamela. She had been approached by a director offering her a screen test when she disappeared. Basil confesses that after quarreling with Dinah, he went home and found the body and dumped it in the Bantry's library. Conway plans to change his will and leave his money to a dance hostel. At 3 am an intruder tries to murder Conway in his bedroom.
Miss Marple discovers that Mark was married to Josie. They murdered Ruby so that she would not inherit Conway's money. The two were also responsible for Pamela's murder.