Devoted wife Tomoko (Nanami Hirose), who deeply loves her husband, works as a maid at the hot spring inn "Kagenuwaya." Meanwhile, Minatsuki (Yumi Kazama), her husband's secret lover, arrives at the inn as a guest. Unaware of Minatsuki's true identity, Tomoko feels an ironic ache each time they meet. However, Tomoko's husband is burdened with massive debt, and to repay it, he cruelly sets a trap that drags both women into his scheme. As the horrifying secrets hidden within Kagenuwaya come to light, the two women are forced into a life of bondage and degradation as "rope slaves●," serving the sadistic desires of their captors.