Dong's mother Taeng teaches Dong and Gym to play badminton as young children. Gym's mother, Tum, struggles to respond appropriately to her son who is on the autistic spectrum.

Dong finds an opportunity to get some badminton practice time in without Gym. While practicing, Dong gets the feedback that his skill set would be better suited for a singles competition, potentially putting him at odds with his mother's wishes for him to play with Dong.

Gym and Dong go to their first doubles match together. However, their preparation is overshadowed when the opposing team endlessly taunts Gym causing him to act out on the court.

Dong discovers a hidden truth about the past of his father, mother, and Aunt Tum.

Dong confronts his mother about her efforts to make up for her past, resulting in an agreement that Dong will make more decisions on his own moving forward, starting with playing badminton singles. Tum takes Gym to a recreation facility for kids with autism where he finds a way to incorporate his passion for badminton.

When Dong breaks his promise to visit home on Sundays, Gym sets out to find his old partner.

Gym and his mother begin to repair their strained relationship. Both Dong and Gym decide they will proceed with playing singles in the upcoming badminton competition.