Tomoko, born and raised on Gekkin Island, has turned eighteen and is bound to leave her home. As she prepares for the journey, a terrifying letter arrives with a mysterious prophecy: 'the blood of countless men will run before her'. Famed detective Kosuke Kindaichi is no bodyguard, but he agrees to accompany Tomoko and get to the bottom of this ominous warning. When one of Tomoko's lovelorn suitors is found murdered in their hotel, terror spreads. And as more family secrets come to light, Kindaichi must act fast before the killer strikes again.