"The difference between damnation and celebration is paper-thin.  
At the same time, Takatsuki and Naoya learn of the urban legend about ""Library Marie"". Apparently if you solve a hidden cipher in the library collection, you'll be cursed. ""The unlucky letter and cursed cipher."" Upon investigating the legend of a demon god in a village, in a grotto they find a skull with a hole in it. Soon after, Takatsuki is plagued by unexpected suffering. How will Naoya help him out of this one?!"