Koibumi to 13-sai no Actress

Fumi Isshiki works as an accountant at an entertainment agency. One day, he is transferred to the management department, where Ayano Haga, a 13-year-old child actress, seems to take a liking to him...? Although he is just a child, she acts more mature than most adults. A dramatic story woven between a professional child actress and her manager! (Source: Houbunsha, translated)