Living his entire childhood in a hospital was never easy for Arashi Ryusei, but being born with a weak body, he had no choice and has not experienced living outside the confines of the hospital. However, his dad, a karate master, has been physically and mentally pushing Ryusei beyond his breaking point. But what he realizes later is that he was only doing it to give Ryusei confidence and a strong will. Now at the age of 14, he is healthy enough to get out of the hospital bed and out in the real world where he has to go to school. Although he has superhuman reflexes, his innocence to everything and naïve personality is both a gift and a curse.