The Player on the Other Side

A five-sided card with the letter "J" stamped on it appeared in Robert York's mail. A day later a huge boulder crushed him dead. It was no accident; someone knew that York was always under the stone wall at precisely 7:30, give or take 10 seconds. And then a card stamped with the letter "H" showed up for Emily York, and all the police protection in the world couldn't save her. Ellery Queen was up against a sick, brilliant killer this time, one who loved to play games. Now it was Ellery's move, and he had best make it quickly . . .