Ночная бабочка

Preparation for the cultural festival have begun. As president and vice president of the student council, as well as a couple, Reiko and Shintaro are given the jobs of keeping tabs on the preparation together. While browsing through campus, they find a fellow student who request they sample the drink he was making for the festival. Suddenly, not knowing why Reiko starts feeling aroused and decides to take Shintaro into a classroom set up as a dark maze. Shortly while inside the two are separated and when reunited, Reiko finds herself unable to control her urges and allows Shintaro to help release her sexual desires but only to find out it wasn't him who found her, Shintaro had already left the room...