"After School! Dungeon High School" is being serialized in the monthly COMIC Ryu! Masanori Yamanishi, the long-awaited first book of the phantom early works is finally gathered at the suspicious antique shop "Kuromori" which is just a recycle shop where Mako Kuromori, who doubles as a shopkeeper, Yuko Monobe, who is still wearing a Noh mask, and Satsuki Seike, a high school girl who aims to change her mind from a shackle, live together with a strange magic item!