Ai to Ao no Kyoukai  

アイとアオの境界, In Between Indigo and Blue, 아이와 아오의 경계

Aiko Uozumi, who works at Rainwater bookstore, is 29 years old and unmarried. Although her family wants her to get married quickly, she lives her life on her own terms. However, one day, she becomes uncomfortable when a man looks at her intently in her workplace. But it turns out that he is her cousin! Additionally, they will be living together in the future.