[Eight Years of Unrequited Love, Tonight.] My wife's younger sister, Momona. I first met her when she was sixteen, one summer. Visiting my wife's family home after a long absence, I felt slightly awkward—but she treated me just as warmly and casually as ever. Ever since then, I couldn't help but feel a strange closeness between us. Now twenty-four, Momona carries herself with a mature charm, yet still radiates a certain innocent allure. My heart races as the night draws near. Falling asleep in the living room that doubles as a guest room, I suddenly see her—there, masturbating, looking exactly as she did back then!? Even after waking, the weight in my chest lingers. Then she whispers, "Onii-san... no, just for tonight, can I call you 'you'?" An unforgettable summer night, an opportunity you can't miss—an unrelenting 80-minute torrent of overwhelming forbidden love from your sister-in-law. Momona (24) is known as cheerful, kind, and well-behaved, yet possesses a strong-willed nature. With O-cup breasts, she fell for me—the man her older sister brought home as a husband—when she was just sixteen. The distance between our homes made any hope seem impossible, and she nearly gave up countless times. But upon hearing that her sister's family would return after eight years, she could no longer restrain herself. Hiding her feelings from her sister, she made up her mind to pursue me by any means necessary. "I'm sorry... I do love my sister." [Content: Kissing, masturbation, handjob, blowjob, titty fuck, cowgirl, missionary, face-to-face seated, floor-focused × ceiling-focused sex included!]