It was very quick-paced, she was head over heels within seconds of their first meeting. The rest is just him coming around and them getting over the obstacles.
Basically: BOOORING

I liked the main song tho, I didn't even realize it before I started humming it randomly. It got stuck in my head, it's very catchy.

Oh one more thing, since the actress is actually a singer from a K-POP group, I expected some "real-time" singing on camera but was disappointed it was all dubbed over with a studio-recorded singing. I guess some K-POP stars really can't sing that well.