A few months ago, the head of the Satsukibe conglomerate, Satsukibe Kazuki, died suddenly. The Satsukibe family was at a loss, but with Ayane Satsukibe, the widowed wife of Kazuki, now at the center, the family somehow managed to maintain peace and stability. Mitsuki, her daughter, helped her mother in times when she felt heartbroken, and began to take care of Tsukiya, her brother-in-law, more than before, and Tsukiya adored having such a kind older sister. But with the death of the head of the family, the fragile equilibrium begins to creak, and a looming shadow falls over them like oil seeping into cloth. Each of their personal ambitions intersecting, they echo as they grow. Desire, lust, betrayal, and deceit begin to hover over them...