Stuck at the bottom of the school hierarchy, Kang-jin, a student with no charisma or money, faces the torment of bullies and endures the worst high school has to offer. Amidst this ordeal, he unexpectedly receives a proposal from a loan shark, Lang, to join forces. Armed with the special skills passed down by Lang while showing that he really cares for the weary students, he swiftly rises to the top of the school hierarchy, even becoming wealthier than his tormentor Nam Young in the process. He also manages to get closer to his crush, Dae-yeong. However, as individuals threatening his position as the High School Loan King begin to emerge, this delightful time seems to be short-lived.

Usury Academy (2023) is a crime action film that features a cast of teenage actors in a thrilling story of school loan sharks. The film is set in a school where private debt, which used to be only found among adult, has spread to the younger generations, with students trying their hands at the private loan business. With this movie, the director wanted to highlight this new reality, where money and violence dictate the relationships. The film stars Yoo Seon-ho and Kang Mina, two rising stars who were discovered through the talent reality show Produce 101. Yoo made his acting debut on TV in 2017, and has appeared in the historical drama series Under the Queen's Umbrella (2022). Kang Mina debuted as a member of the girl band Gugudan. She has been known for her roles in the drama series 20th Century Boys and Girls and Hotel del Luna. For both actors, this is their first film role.