Onikko: Mystery Kessakusen is a collection of three distinct stories. The first story is titled "Onikko," followed by "Aoizameta Onna," and finally "Zou no Naka: Yuugao no Hana no Youna Hito." Each narrative presents its own unique mystery, exploring various themes within the genre. The collection offers readers a diverse set of short stories, each with its own characters and setting, contributing to an overarching atmosphere of intrigue and suspense.