Ranran wants to marry him, but her boyfriend is hesitant about marriage. She plots that if she gets pregnant, they'll have to get married! But there's no sign of pregnancy. Then she notices her sister has been married for several years and has given birth multiple times. Her sister is a divorcee remarried; she didn't get pregnant with her first husband. However, since marrying her current husband, she's given birth multiple times. 'I'll have my brother-in-law cum inside me a lot'... An evil pregnancy plan begins…
