Sakuya, who was stabbed to death in the throat with a knife, comes back to life thanks to his unique constitution.
The body Sakuya finds is that of Watanoya Nejihiko, the son of the president of Watanoya Confectionery, a famous sweets manufacturer.
Sakuya searches for the person who killed him and Nejihiko. As he continues his investigation, using the scene he saw before he died as a clue, he receives a call from Yuriu saying that she has found the cat she was looking for. That cat holds the key to solving the mystery of the case. Meanwhile, the shadow of the killer looms behind Yuriu as she holds the cat...

A water leak at the detective agency forces Sakuya and Lilithia to take refuge at the Kowloon's Hotel.
There, they find Yuri and the film crew shooting their next project, as well as, for some reason, the familiar detective Manroki.
Manroki explains that the director received a threatening letter from someone called "the dog-headed bellboy."
Sakuya and the others decide to patrol the hotel to make sure the film crew is not harmed.
Along the way, Sakuya encounters a suspicious man wearing a dog mask...