When two people who have always hate eachother were force to do an arrange marriage by their parents, how can they get along?

Perth is the campus heartthrob everyone knows-handsome, popular, and effortlessly charming. Known for his wild antics and boyish playfulness, he's never one to take things too seriously, despite being secretly brilliant and a whiz on the electric guitar in his Music major. But his carefree days get a shake-up when a mysterious new student transfers in: Santa, fresh from an exchange program in Korea. With a face like a K-pop idol, a quiet demeanor, and an intense talent for dance, Santa becomes an instant sensation, drawing fans away from Perth in droves. As Perth's ego takes a hit, he finds himself facing a new kind of competition-and a rivalry that might reveal hidden sides of both of them. Is this the start of an intense rivalry, or will unexpected events lead to something that changes their lives forever?

Perth and Santa are both elementary school teacher. Santa loves kids so much but Perth doesn't like kids. Even though, he didn't like kids he chose to be a teacher because he wants to follow his boyfriend. The two of them are happy couple however, everything changed after Santa got into a car accident causing him to have a memory loss and suffer from trauma brain injury which reverted his mental state to a 7 years-old-kids. After Perth takes Nong Santa back home, there are days when Perth doesn't get any respite from children.