5歳になる堀口元気は、ドサ回りのボクサーであり父のシャーク堀口と共に、各地を転々としながら生活を送っている。そんなある日、父のプロボクサー復帰が決定。慣れないフェザー級での試合ながら連勝を飾るが、天才ボクサー・関拳児との死闘の末、帰らぬ人となってしまう。やがて時が経ち、世界チャンピオンとなった関は、不敗の王者としてボクシング界に君臨する。一方、元気は母方の祖父母に引き取られ、田舎で何ひとつ不自由のない生活を送っていたが、志半ばで倒れた父の夢を実現するため、密かに練習に取り組む。元ボクサーの三島栄司、恩師の芦川悠子らの支えもあり成長を遂げた元気は、中学卒業と同時に単身上京、関を倒すべくプロボクサーを目指す。 <br /><br />(For Non-Japanese Viewers) <br />When you watch the video, please click the Gear icon "⚙ "in the top-right corner of the screen to access the subtitle options, then select your language if available. <br /><br />Five-year-old Genki Horiguchi lives a nomadic life traveling from place to place with his father, Shark Horiguchi, a traveling boxer. One day, his father's return to professional boxing is decided. Despite fighting in the unfamiliar featherweight division, he achieves consecutive victories. However, after a deadly battle with the genius boxer Kenji Seki, he passes away. Time passes, and Seki becomes the world champion, reigning as the undefeated king of the boxing world. Meanwhile, Genki is taken in by his maternal grandparents and lives a life of comfort in the countryside. Yet, driven to fulfill his father's unfinished dream, he secretly trains. Supported by former boxer Eiji Mishima and his mentor Yuko Ashikawa, Genki grows stronger. Upon graduating middle school, he moves to Tokyo alone, determined to become a professional boxer and defeat Seki.
