The husband had a sister, the youngest of her kind ...... who had been spoiled from childhood, and for whom her brother had always given up everything ...... but he had never thought that he would give up his wife as well! ? ...... When Reina, who has come to Tokyo to continue her studies, comes to live with her, her beautiful wife Nana falls into a forbidden relationship between the step-sisters ...... Now, there's no stopping them... ...