Aya, a career woman working for a major company, is well-liked in the company and is always smiling, so people around her think she is a calm person, but in reality she has such a strong libido that she cannot maintain her ego without masturbating. A frustrated monster of insatiable sexual desire, created by years of brainwashing, is suddenly visited by Himari, a junior at work who missed the last train, and is half-forced to stay over... Aya was able to hold back from masturbating due to the sudden, unannounced, abstinence from sharing a room, but she gradually loses her reason and starts masturbating with her junior's personal belongings...