Based on the erotic game by Lune. Advanced series from Jutaijima. The school trip is very fatal. A ship carrying students for a holiday trip, was suddenly crushed by a storm, fortunately those who survived, were stranded on a strange island. On the Island, the behavior of girls becomes strange due to a strange virus infection. The virus makes the girls feel aroused and can not control themselves. The only way is to give sperm regularly, it can make them immune from virus attacks. If they are not given enough sperm, then it will make a heart attack from an unrelenting arousal....