After her husband's sudden death and her company's bankruptcy, Shoko Akase lost everything and was evicted from her home. The only person who supported her was her father-in-law, a kind and warm presence who became her sole lifeline. However, he had one strict rule: she was never to enter his private "workroom." Curious and unable to resist, one night after confirming he was asleep, Shoko sneaked into the forbidden room. Inside, she discovered an overwhelming array of extreme BDSM equipment, far beyond anything she could imagine. Overcome with shock and fear, she was caught red-handed by her father-in-law. In that instant, their relationship took a dark and irreversible turn, plunging Shoko into a world of tight bondage, cruel humiliation, and merciless training.