The sickly reincarnator couldn't forgive that his older brother was trying to break off the engagement.

Irina was hit by a car near a shrine in her previous life and died. Now she has been reincarnated as a sickly girl, but in a world where medical knowledge is underdeveloped, she only receives proper care when her brother's fiancée, Lady Sharia, is present. However, her brother lacks medical knowledge and blames Lady Sharia... and then her brother summons a saintess for treatment...