Overview:

Go Jeong-woo, a female psychology professor, gets drunk after witnessing her boyfriend cheating on her on Valentine's Day. Kim Dae-han, a college student who followed him, sees her staggering near the lake and tries to save her, but they all fall into the lake and the two spend the night. Afterwards, what will happen to the romance of the two people who met again as professor and student in a university lecture room?