Quiet girl Reina had always lived a pure and peaceful everyday life. However, her school's male teacher becomes interested in her and invades her room under the pretense of a home visit. Under the guise of checking her behavior, the teacher begins rummaging through Reina's bag. From it, he "discovers" a cigarette he had planted beforehand, and accuses her of smoking. The timid Reina denies it, but the teacher forcefully attempts sexual assault under the pretext of discipline. As a result, Reina's innocent heart is threatened...