Starts with a number of chapters about Etsuko, a female teacher with a "shota" taste. This is followed by a multi-chapter story arc called "Ruin", about the erotic adventures of two sisters. The book ends with...

Akira is looking for a girl to share an apartment with. Then, after meeting an applicant named Hotaru, it turns out... he's a guy! Hotaru is allowed to stay for just one night, but...

Original synopsis found here