Kameda Kamerou is a normal second-year high school student who leads a dull school life. His true feelings are hidden behind his ribs.

One day, the news that his best friend, Kaerugawa Erutaka, helped others spread quickly and caught the attention of a high-ranking group, including the school's superstar, Raionji Raiou, who is aiming to become the student council president. Kaerugawa suddenly joins them, and Kameda is tormented by jealousy and an inferiority complex. How will their friendship go? And on the day of the student council election, a session of "bone-to-bone collision" begins?!

When the bones change, the world changes. This is a story of conflict and growth between certain high school students and ribs.