Hajoon has been crushing on Eun-woo ever since they started college together, but he hasn’t had any opportunities to get close with him. At least they have a class together this semester: a lecture taught by the popular Professor Seo Joohyuk. Hours after the first class, Hajoon remembers he left his assignments in the classroom. Upon reaching the lecture hall, he becomes witness and accomplice to a series of private lessons Joo-hyuk is giving Eun-woo—lessons that unleash his own deepest, riskiest desires.