to rid himself of the attraction that he felt for Nanoka when he first met her. Instead, his love and desire continue to grow, despite his attempts to fight them. Entering womanhood, Nanoka also develops feelings for her older brother, only increasing Koshiro's struggle. In near desperation, he moves out of the family home to remove himself from temptation and attempts to keep his coworker, Kaname Chidori, from finding out the truth behind his brusqueness with Nanoka. However, the solution is only temporary, as Nanoka begins visiting Koshiro regularly, cooking him meals and spending time with him. Eventually, unable to resist their feelings anymore, they share a passionate kiss and have sex with each other. Unsure of what to do now that they have broken a societal taboo, they visit their parents, before contemplating committing suicide together. In the end, they decide to live, and to continue their relationship. Characters A 27-year old largely-built man usually sporting a five o'clock shadow, Koshiro works for a marriage-arranging company and lives with his divorced father. He had almost completely forgotten that he had a little sister until she came and moved in with them. He finds himself battling with society's definition of what an older brother should be and his sexual and romantic feelings for his sister. Nanoka is a 15-year-old high school girl who has moved to Tokyo to live with her father and older brother to attend school. A bright and active girl, she grows increasingly fond of her older brother, though is regularly annoyed with his brusque nature. Her friends unwittingly tease her about having a "brother complex", not realizing that Nanoka is actually falling in love with him. Zenzo is Koshiro and Nanoka's father. He is prone to bouts of hysterical worry and cares for both of his children, though in particularly Nanoka. Makie is Koshiro and Nanoka's mother. Until moving to Tokyo, Nanoka lived with her mother, who runs a hair salon. She rarely sees Koshiro, though she speaks to him fondly when he visits. Kaname is Koshiro's supervisor and appears to be around his age. While she is often critical of his sloppy appearance, she encourages him where she can. When Koshiro first sees Nanoka outside his job, Chidori encourages him to go on a date with her, not learning until later that Nanoka is his sister. She eventually becomes suspicious of the siblings' relationship, and