Concerned about her son's poor grades, Chisato consulted her homeroom teacher, but the teacher's reaction to her son's poor performance was not good. Worried, Chisato enlists the teacher and tries to get her grades up somehow. However, as a result, Chisato became addicted to the charm of pleasure that attacks men. After that, Chisato, who pretended to think for her son, poisoned the men involved in her son one after another.