Lust is a manga about a woman who is constantly affected by an unseen entity, leading to persistent arousal. This mysterious force originated during her school days when she teased a boy, playing with his emotions. The boy's shadow detached from him and merged with hers, causing him to vanish. Now, this shadow entity follows her, both protecting and molesting her, making it difficult for her to lead a normal life, even in the presence of her husband.