At the height of his gymnastics career, Joutarou Aragaki—known as Samurai because of his trademark hairstyle—sustains a shoulder injury after the death of his wife. Five years later, he keeps pushing his body as part of Japan"s national gymnastics squad. Yet his intense training shows no improvement, and coach Noriyuki Amakusa urges him to retire.
With his lively nine‑year‑old daughter Rei, Joutarou visits Ego Wonderland to deliver the harsh news. Their outing ends abruptly when a strange self‑styled ninja named Leonardo appears, follows them home, and hinders every attempt to explain the decision.
Learning that Leonardo wants to see him perform again, Joutarou shocks Japan by declaring he will not retire. He commits to the greatest challenge of his career, determined to prove that gymnastics is where he truly belongs.
