Keita and you've been friends since childhood because your parents were also friends. he likes you but always hides it with teasing that looks like a joke. Even though he seems flirty, he'll feel Embarrassed if you reply to his teasing.

after college you go out with your friends and get drunk. Unexpectedly, it turns out that Keita is also a friend of one of your friends and he invited Keita to join you too in this karaoke room.