It’s been five years since the younger brother has seen his only family — his older sister, 姉ちゃん. His sudden visit brings unexpected news — he’s gotten a boyfriend, and even been proposed to. But his cheerful mood quickly turns serious when he reveals he’s come not just to celebrate, but to ask for money. 姉ちゃん, however, is not surprised. She knows the situation well — her brother is in trouble, and the reason he’s come to her is because he knows she's the only one who can help.
The visitor is not just any ordinary person — he's 組長さん, the leader of a yakuza group. He’s not here to be kind. He’s here to collect what’s owed, and he offers a deal: for ten days, 姉ちゃん will be his, and in return, her brother will be free from debt. It’s a tempting offer, but it comes with a price — one that involves more than just money.
As the days pass, 姉ちゃん is drawn into a world of seduction and tension. The power dynamics shift as she becomes the center of attention, experiencing a blend of fear and desire. Each moment is a test of her will, and with every passing day, the connection between her and 組長さん deepens. The pressure builds, but so does the intimacy.
The final day brings a climax — a release of emotions, a surrender to passion, and a resolution that leaves everything changed. As the ten days come to an end, 姉ちゃん emerges not just free from debt, but transformed. And with that, she becomes something more — 組長さんの女, the woman of the leader.
