The strangled dead body of Hiroshi Hatano, accounting section chief at the longstanding apparel company Edaka International, is discovered in his apartment in Tokyo. At the scene, Inspector Totsugawa and Detective Kamei find out that a mysterious email stating "I'll be riding the Super Ozora 5 tomorrow" was sent to the victim's cell phone the night before. The sender, Manami Furuya, an employee of Edaka International's Planning Section, has strangely terminated her cell phone service and hasn't ...