As the national team selection marathon approaches, Daegu is pulled aside by Sangman, while Haengju watches anxiously from the marching band. A childhood flashback reveals Daegu narrowly losing to Jiman in a neighborhood marathon. Determined to win first place and buy Haengju a birthday gift, Daegu runs ahead, leaving the crying Dae-o behind.
Daegu begins training with his teammates for a half-marathon. After throwing an envelope of money at Jiman, he remains angry despite Jiman and Haengju reminding him that friends should help each other. During a relay race against high school athletes, Daegu makes up for two runners and leads his team to victory. He then urges his father not to sell the shop, declaring that he wants to run again. Later, Haengju learns at the public bathhouse that Daegu has resumed training.
Daegu signs a contract with Coach Hwang to serve as Jiman’s pacemaker, using the money to settle his father’s legal fees. As they train for the national team selection, Coach Hwang questions why Daegu’s performance drops after 20km, but he refuses to explain. Haengju becomes angry after learning that Jiman helped her get into the symphony orchestra and insists they remain just friends. Resentful that Daegu cannot understand her feelings, she is about to confess her love when Jiman spots them together.
Just before the finish line, Daegu overtakes Jiman but collapses as his legs suddenly give out. Jiman wins with a personal best, while Daegu wakes in the hospital to Sangman calling his name. Haengju encourages Daegu to be honest about his feelings as she prepares to audition for the symphony orchestra again. Despite Jiman’s improving times as a national team member, Daegu joins the city hall team with his teammates, determined to overcome his guilt over his older brother and keep running to the finish.