They were friends. Never exceeded the friend-zone limit. 

Hae Yonji was a very typical average high school student and as I say typical, really typical. She was not pretty, nor rich, or even clever. As she entered the senior year, she felt the outmost pressure to graduate high school with flying colours. 

Seoul High School was one of the cluster school in Seoul, and has been regarded as one of the prestigous school. But of course, not everyone from the school was clever, including Yonji. 

Park Jaehyung, mostly known as Jae, was that student who scored in his exams. He was considered quite good-looking, but was not as famous as his friend, Younghyun, who was the school's head boy. 

Both Jaehyung and Yonji were schoolmates and batchmates, at least that was what they were thinking. They were never close to each other, before Jaehyung made the first move.

"How's your result for the last exam?" - Jae

"Why do you even bother?" - Yonji