Kazuma Naruse mistakenly believes that his beloved girlfriend, Maki Mizuhara, fell into the sea and died. After taking in her daughter, he is deceived by Yukina Kirishima, the daughter of a billionaire, and ends up welcoming a fake daughter in place of his real one. His true daughter, Mio Naruse, is abused and driven out of the house. Meanwhile, Maki Mizuhara, who was thought to be dead, returns with her daughter and exposes the fake daughter's true identity. Mother and daughter join forces to carry out their revenge, ultimately making Kazuma Naruse realize the truth and suffer deep regret.