Mark, a Korean American arm wrestler, travels to South Korea to compete in the World Arm Wrestling Championship. During his stay, he meets a young woman named Jin-sook who claims to be his long-lost sister. Mark is skeptical at first, but as he spends time with Jin-sook, he starts to believe that she could be telling the truth.
Mark's parents, who had given up hope of ever finding their daughter again, are overjoyed to hear the news. Mark decides to help Jin-sook track down their birth mother, hoping to reunite their family once and for all.
As Mark prepares for the arm wrestling championship, he also tries to bond with Jin-sook and make up for lost time. However, tensions start to rise as he realizes that Jin-sook has been keeping a dark secret from him. The revelation threatens to derail their budding relationship and Mark's chances of winning the championship.
In the end, Mark and Jin-sook reconcile and he manages to win the championship, becoming a true champion not just in arm wrestling, but in life and family as well.
