Based on the erotic game by Dwarfsoft. 
 
Ichirou Tani has a thing for hostess bars and spent all his company's money at them. Fleeing into the snowy mountains, his car breaks down during a heavy storm and he's forced to wander in search of help. That's when he stumbles upon 
 
Inside her meets the widowed head of the family, Rurie Munakata, her daughter Nakoto, and their maid Ren Takahara. And nobody else... His passions were inflamed by the residents' beautiful faces and excellent bodies, but he feared they may call the police if he tried anything. And so he abstained... later, at the dinner table, Nakoto was quite rude with Ichirou. As an apology, and because of the bad weather, Rurie asks that Ichirou stay there as Nakoto's tutor until Spring. He had no reason to refuse. 
 
He spent his first night at the mansion thinking on the events that lead him there. His embezzlement, his escape, becoming Nakoto's tutor... And that's when Rurie crept into his room. Sneaking into a healthy, virile man's bedroom at night? At her age, there's no way she didn't know what she was doing... And indeed, it progressed to sex. Ichirou had barely internalized what was happening when Rurie spoke... "If you want more of this, you'll need to take my daughter's virginity..." Before Ichirou could even ask a question, Rurie answered "She's at that age, you know... but out here in the mountains she doesn't meet a lot of men. As her mother, I'm worried." 
 
He didn't believe her, but he was under her spell... he'd do it, and with her full consent. The next day, Ichirou's job as a tutor began. Nakoto was a difficult student, but she harbored no ill will toward her teacher. Since he had Rurie's permission, he couldn't take it any longer. He pushed Nakoto onto the bed. But when he lifted her skirt, he found a tightly-locked chastity belt. Nakoto smirked "If you want to have sex with me, get mom pregnant..." 
 
A mother who wants him to have sex with her daughter... A daughter who wants him to impregnate her mother... And the maid who serves the both of them... The curtain rises on a shocking four-way tale of debauchery! 
 
(Source: DLsite English) 
 
Note: A demo was available to the players of RPG browser game Aku no Onna Kanbu: Perigee New Moon (悪の女幹部ペリジーニュームーン) on August 4th, 2021.