START-571 Maternity Ward: A junior female doctor who is getting married next month is having her future happiness destroyed as Haru Shibazaki repeatedly ejaculates thick sperm inside her during a break in her night shift.

Haru Shibasaki, a surgeon, deeply trusted Nitta, a senior doctor who had been under his care since his days as a medical resident.Nitta is a kind senior with a good reputation, but in his private life he has little experience in love, and he develops a crush on Shibasaki due to his friendly nature and sense of closeness.One day, Nitta confesses that he will marry the patient he previously saved.Nitta takes it as a sudden betrayal and holds a grudge against Shibasaki...