All Lee Seung-hyeon wants is to pass his final summer class, taught by an infamously strict professor. Seung-hyeon has already failed once after missing the final presentation due to a misunderstanding in a crowded train. This time, he is determined to ace the group project—if only a certain evasive classmate, Seo Chaejun, would show up and do his part. Seung-hyeon tracks Chaejun down and realizes Chaejun was behind the train incident that led to his previous failure. Determined not to let the same guy ruin his grade twice, Seung-hyeon insists Chaejun participate—only to discover that Chaejun suffers from chronic insomnia that is relieved solely through sexual acts. While most would back off, Seung-hyeon sees a chance: if it gets Chaejun to class, he is willing to go all the way. [Written by MAL Rewrite]