Nana dreamed of a small, quiet happiness with her kind and gentle husband, despite his frail health. But when her husband was swindled as a guarantor into massive debt, the burden broke his body, landing him in the hospital. Harassed by debt collectors and pushed to the edge of despair, Nana is approached by her husband's older brother—her brother-in-law. He offers financial help in exchange for her body as collateral. At first, she submits solely to repay the debt, but gradually, she is overwhelmed by her brother-in-law's powerful physique and raw desire. As she is repeatedly taken by his passionate advances, Nana sinks deeper into a whirlpool of pleasure, descending into a hell of ecstasy. Deep within her heart, she whispers, "Brother-in-law... please, forgive me."