We were taken to some island, thinking it was a school trip. What was declared there was the beginning of a battle to the death. It seems only five people can board the boat that will come 28 days later... Nishibe, indecisive and timid, is bewildered by the sudden event. Can he really survive? The cute and deadly mouse death game begins."

修学旅行だと思って連れてかれたどこかの島。そこで宣告されたのは殺し合いが始まることだった。２８日後に来る迎えの舟に乗れるのは５人だけらしい・・・・。突然の出来事にうろたえる優柔不断で弱気な西部（にしべ）君。果たして彼は生き残ることができるのか。かわいくてみえてくらっちゃう、ねずみデスゲーム開幕。