SERO-0243 follows a high school girl who, after escaping a groping incident, secretly begins masturbating in a secluded spot.

The groping attempt failed, and while he was enjoying his act, the target high school girl escaped the moment the door opened! That won't do, so he followed her, only to discover she was masturbating in the warehouse… A once-in-a-lifetime plot twist, and of course, he just barged in!