In Sangwoo Choo’s meticulously organized world, Jaeyoung Jang is nothing more than a grammatical mistake. As a strict rule follower, Sangwoo refuses to give credit to classmates who slacked off on a group project, a decision that unexpectedly prevents his senior, Jaeyoung, from graduating. The two are like oil and water, seemingly impossible to mix due to their clashing personalities. Forced into each other’s lives, Sangwoo must now face the ultimate challenge: can he “fix” Jaeyoung, the one lexical flaw disrupting his otherwise perfect life?