Nagashii Kouhei Manga

Kobayakawa is an unsocial student who lives an extraordinarily ordinary life. One day he meets a girl named Hoshino who has a secret that nobody knows except her and her sister, one day when Kobayakawa was saving a cat with Hoshino's help, he discover her secret and as a request for her sensei, Kobayakawa has to make-up Hoshino to keep the secret untold.