Watari, Tsubaki and Kousei are close friends.
From the first episode, Watari is shown to be athletic, a womanizer and is popular. (Captain of the soccer team)
Tsubaki's outgoing, friendly and caring.
Kousei's kind, caring, soft-spoken, polite.
So, Kaori Miyazono is a violinist, and has a crush on Watari.
Kousei's also got a job which transcribes new songs for karaoke and stuff.
The gears start to move when Tsubaki receives a phone call from someone and she tells her that she will definitely do what she was supposed to do. It's revealed the next day when she asks Kousei to follow her to Watari and this girl's meet-up so that she doesn't become the third-wheel.
There was a flashback where Kousei was playing magnificently in a competition when he was eleven, however, one could see his eyes were dull. After that, he stopped and started crying. Later, Kousei said that during that autumn, he couldn't play the piano anymore.
