On our wedding anniversary, my wife was discovered at a hot spring inn in her hometown by playboys from her former hookup group, leading to an unforgettable threesome that lasted until late at night... The entire story of how my wife, whom I had so painstakingly endured, succumbed to the allure of huge penises. (Amamiya Kasumi SORA-590)

With over 100 experienced partners, Kasumi Amamiya is a stark contrast to her carefree student days. Since entering the workforce, she's focused solely on her boyfriend. After three years with her hardworking boss, they finally married last year. On her first wedding anniversary trip to the hot springs of Yamanashi, she encounters her university classmates. "I never want to see these guys again..." They were members of the same casual sex group Kasumi once belonged to. Kasumi vows never to succumb to them, but memories of the past gradually resurface...