Robin Sena's daily routine takes her through a park, after her morning prayers. When she discovers that three dead bodies were discovered there prior to her coming to Japan, she and Miho Karasuma decide to investigate further, unaware of the danger that they're placing themselves in as their foe can flay a person alive.

Robin's Vespa runs out of gas in the middle of nowhere, but she's soon rescued from an approaching thunderstorm by Eiko Yano, who offers her a lift back into town. But when her benefactor is found dead the very next day, Robin finds herself mixed up in a case where the size of one's foe is not indicative of the danger one faces.