The narrative centers on Ken, a young man from a wealthy family who was orphaned at an early age because of his relatives' ties to the Yakuza. He grew up to be a high school delinquent, recognized for his fighting skills. His sole motivation for taking action stems from his romantic feelings for a classmate named Yumi. Upon discovering that she had decided to move to Korea to train as a police officer, Ken abandons his life in Japan and attempts to follow her path. Due to unexpected circumstances, he accidentally becomes the leader of a local gang and attempts to keep this fact hidden from Yumi. Under his leadership, the gang is renamed the Sun-Ken Rock Group.