A man meets his end when he is hit by a car while protecting a child, only to wake up reincarnated in a fantasy world as Yumie Granbell, the extraordinarily beautiful daughter of a count. In his past life he was an otaku hikikomori, but now he looks into a mirror and sees a reflection that is like an angel, a girl of peerless beauty. The Granbell family is a prestigious and influential magical house, and Yumie believes he has hit the jackpot in his new life. However, he soon discovers that the family is on the verge of collapse. When he cheerfully leaves his room to greet his new mother, he receives a painful slap and is told to be quiet. He learns that Yumie is an illegitimate child who is abused in the household, and the resulting strain has caused his new parents relationship to deteriorate to the point of daily arguments. Realizing that the crisis is spiraling out of control and that he is partially the cause, the protagonist decides to use Yumies overwhelming cuteness as a weapon to bring smiles back to the family, solve every problem, and restore the Granbell name to its former glory. The story follows the protagonist's efforts to achieve the loving family he always dreamed of by becoming a beloved character in his new life. The manga is created by author Jajamaru and artist Atami Shin.