After marrying wealthy tycoon Soichiro, Kaori finds herself entangled in a web of complex relationships within their luxurious mansion. Her daily life is disrupted by her greedy stepson and his wife, who covet the family fortune, as well as a devoted secretary who harbors feelings for her. Meanwhile, Aoi, the son of her husband's former mistress—once cast aside—returns seeking revenge. Drawn to Kaori's kindness, he forms a twisted bond with her, pulling her deeper into a forbidden connection. However, the observant secretary soon senses their affair and, driven by obsession, steers Kaori toward a dangerous and perilous path.