Mahiro Ichiki's heart had been captured by her beloved older brother's overwhelming affection. However, when he left for college in Tokyo and began cohabiting with a woman he loved, her feelings gradually turned cold, ultimately leading to the collapse of their relationship. Depressed, he dropped out of university, lost all motivation to work, and became a shut-in. Meanwhile, after the passing of her adoptive grandmother, Mahiro moved to Tokyo and sought refuge at her brother's place. Overjoyed at the prospect of reuniting with the brother she adored, she instead encountered a completely different person. He had undergone a drastic transformation, turning cruel and vicious as he kidnapped and imprisoned her. Each step he takes reveals deep psychological turmoil and twisted love, driving the story into increasingly intense, emotionally harrowing territory.