Three murders occur in Tokyo, with numbers left at each scene, possibly indicating the location of the next. Detective Nitta Kosuke investigates, suspecting the next murder will happen at Hotel Koruteshia Tokyo. He goes undercover at the hotel, where he clashes with front desk worker Yamagishi Naomi. While Kosuke focuses on catching the killer, Naomi prioritizes guest safety. As they learn to work together, trust develops between them. Who is the murderer?
