Jung Jae-chan was a dense boy—a bad student, until eventually, his father, wanting to at least see his grades improve, hired him a tutor: Lee Yoo-beom. After a while of his grades not improving, Yoo-beom talked him into manipulating his grade card to reflect impossibly higher grades; this would increase Yoo-beom's salary with his father, and he would split the money with him so he could buy a motorcycle. His father briefly becomes so proud of him that he boasted about is grades to his colleagues at the police station he worked at, but their ruse was caught when his father questioned how he was able to buy a motorcycle.
A police officer Choi Dam-dong comforted Jae-chan after seeing his father's disappointment, telling him to move on quickly but to never forget his mistake and learn from it, urging him to truly make his father proud.
Shortly after buying his motorcycle, while out riding it with Yoo-beom, the latter crashed the motorcycle into a store, causing damage. Yoo-beom blamed it all on Jae-chan when he refused to take the blame, making Jae-chan realize how unreliable the boy was. For this, Jae-chan and his father spent the night outside there house, chastised by his mother. While pretending to be asleep, he overheard his father's message for him about wanting him to achieve more than he ever did, and this touched him, making him more determined to make his old man proud. He told his father as such, and his overjoyed father suggested that he try to become a prosecutor—advice Jae-chan took to heart.
He never had the chance to show him his efforts, however, because moments after telling him this, a runaway soldier shot him inside a convenience store. At the shared funeral held for his father and another heroic victim of the soldier, he met the other victim's daughter, whom he thought was a boy. The soldier turned out to be Officer Choi's brother, and Jae-chan furiously attacked him for his brother's actions. Officer Choi left soon after, but Jae-chan went after him because "Chipmunk"—the other victim's kid—wanted to talk to him. They followed him to a lake and found him attempting suicide. Jae-chan rushed after him to rescue him and convinced Chipmunk to help him, despite the other kid's reluctance to save the brother of the man responsible for their fathers' deaths. Jae-chan was able to rescue him but lost consciousness underwater before Chipmunk could pull them out. She gave him CPR and revived him. Chipmunk left with only a note at the hospital they were taken to.