Yuki Mishima was hospitalized with her husband's support to treat a chronic illness she had long suffered from. But the reason she now finds herself in this situation is not because she has forgotten her past. During her school days, she relentlessly bullied her classmates, driving one girl to develop severe school refusal. Though Yuki herself had nearly erased those memories, the victim—and her sister, a nurse—had clung to their hatred for ten long years, patiently waiting for the moment of revenge. Now, those old wounds are reigniting as part of a new, twisted game.