Pluto

Pluto is a story about elite high school seniors, the top 1% who are prepared to go to extremes to get into prestigious universities. June, the main character, was transferred from the general high school to the prestigious high school. The first examination result drives him to despair. One day he finds out that some high-ranked students are sharing secret notebooks which contain important information.
To gain these notebooks he begs themembers of the secret circle. Thus they order him to accomplish some missions to get the notebooks. In this process he himself changes. What led to this change?