Chika goes to school, however a bunch of classmates ask her help to solve the disappearances of several classmates. Kyouka appears to help and they discover that the reason behind the disappearances was a drug developed by the mafia that turned people into animals.
In the end they are saved by a green version of Hyouka and confront the true mastermind of the plan, a experience created by the department of supernatural affairs known as Electric butterfly.
姫宮家から逃れて平和で普通の学園生活が送れると思っていた千花。だが、転校初日に女番長の桃草愛智を負かしたことでその座を譲られた千花は、愛智や仲間の山口聖、罪木静から「番長」や「お姉様」と呼ばれ慕われるようになる。そんなある日、滅多なことでは休まない学園の生徒たちが、理由も告げず学校にこなくなり…。
