Yurina, a married woman appointed as the leader of her neighborhood association, is brimming with enthusiasm. She immediately investigates past ledgers and finds unaccounted funds, so she consults with the veteran Tonegawa about it... Tonegawa had known about this fact all along and had been covering it up. To silence Yurina, he sends in Hyodo, a young man from the same neighborhood... Unaware of anything, Yurina is swept away by his momentum and gives herself to him, despite being married. But little does she know, this marks the beginning of her nightmare...
