Tsukumo works hard at her part-time job at a convenience store to earn money for her favorite band and dates with her boyfriend. But the manager of the part-time job is a typical Showa-era perverted old man who always messes with Tsukumo and enjoys himself on his own. One day, while working at the store, Tsukumo witnesses the manager stroking his dick in the back room... Tsukumo is shocked to see something she didn't want to see, but what's more, she is shaken by the size of the manager's dick. Invaded by the manager's clutches, she becomes a dick-crazed man... Even though her boyfriend is nearby, she sucks the manager's huge dick. The more she works the shift, the more greedy the uniformed part-time girl becomes... She has to replenish her balls with sperm while refilling her drinks, or her sperm stock won't keep up with the age-gap sex