The 9-word clue was one of 9 cryptic notes that had been sent to taunt Inspector Queen and Ellery 9 days after the murder. Nino Importuna had been obsessed with the number. He had lived by it. Now the killer who brought a trio of gory deaths to Nino's 9th-floor penthouse at No. 99 East was camouflaging his identity in a jungle of 9s. And daring Ellery to find him. The case was destined to be a dazzling contest of wits-to the 9th degree!