Mana, a sickly high school girl, fainted while reading the final volume of her favorite novel Gran Avere and found herself reincarnated as Leticia, the sister of Serios, the Ice Prince who tragically dies the last boss of the novel! Even after her reincarnation, Leticia is still sickly and weak, and is busy making cheat amulets and making contracts with fluffy spirits and a talking holy sword in order to save her beloved brother Serios, her most favored hero! Leticias actions begin to change the course of the novel...? The fantasy of a young reincarnated girl who is doted on by her most favored older brother and avoids death flags begins!