Hyun Bin is a first year student meets Bae suzy is a final year student and daughter of a police officer. Everyone in the campus likes Bae suzy at last, even Hyun Bin's friends likes Bae suzy. Bae suzy gets close to Hyun Bin and they both become good friends. Bae suzy is a writer of a book about a sex worker monalisa's life and she knows the sex worker personally. The sex worker is pregnant and one day she gets labour pain. Bae suzy along with Hyun Bin takes her to the hospital. The sex worker bears a baby girl and keeps the baby's name as Bae suzy. Hyun Bin holds the baby and gets emotional. Bae suzy always saw Hyun Bin as a fun, loving and cheerful guy. Seeing Hyun Bin as innocent and emotional Bae suzy suggests Hyun Bin to discover .
They become close friends and starts to go out together. In the girls hostel, girls were celebrating the final year students send off party meanwhile even the boys enter the hostel and everyone starts to sing and dance. The boys leave the hostel, Bae suzy and her friends decides to drink whereas Bae suzy refuses to do so but due to her friends she sips a bit of vodka. While dancing Bae suzy falls from the hostel rooms window and dies. Hyun Bin gets upset. Everyone starts to speak about Bae suzy in a wrong way even Bae suzy's father gets angry about Bae suzy getting drunk. Seeing all this Hyun Bin gets angry and starts to beat his senior.
After three years Hyun Bin is in his final year, he becomes stubborn and rude. He is in the final year and Jasmine his junior doing her first year in electrical stream falls in love with Hyun Bin. Hyun Bin and his friends get apart due to fight and he forms another group.
Hyun Bin stands for the college election and also wins the election and becomes president of the college. Jasmine wants to change Hyun Bin. She wants to make Hyun Bin as he was in the first year of college. Jasmine and Hyun Bin go for a long drive where Hyun Bin and Jasmine do some mischievous things which brings a smile on Hyun Bin's face. Jasmine takes Hyun Bin to Bae suzy''s house unknowingly. Hyun BIn sees Bae suzy's parents and her photos in the house and gets emotional. Bae suzy's father apologizes for not trusting his daughter and thanks Hyun Bin for the diary which he gave after Bae suzy's death. Bae suzy's dad gives the diary to Hyun Bin and asks him to read it. Hyun Bin leaves the house and on his way he goes to the sex worker's house whom he and Bae suzy had helped during her labor pain. Hyun Bin sees the sex worker's child and gets emotional as her name is also Bae suzy. Hyun Bin leaves the house and meets Jasmine, she tells him that he is lost in his past and asks him to come to the reality and leaves from there giving an emoji badge to him.
Hyun Bin gets stuck in Jasmine's words and leaves on bike to another place. Hyun BIn decides to sell the car which he and his friends bought in the first year and give the money for the sex worker's child's education. In his trip Hyun Bin learns that he is in love with Jasmine. He goes back to college. It was his final day in college. Hyun Bin writes two letters, one to Jasmine and another one to the Principal stating that he and his friends locked him in the car and blamed his other friends. In Jasmine's letter he writes that he loves her and wants to be with her. Hyun Bin and his friends get back together forming the same bond as first year. Principal forgives Hyun Bin and his friends without reading the letter. In the send off party Jasmine comes with the letter and tells Hyun Bin that he is really a good human being and he accepted his mistake and asks him to give the letter to the Principal and not to her. Everyone gets shocked and Hyun Bin realizes that he swapped the letter. The Principal reads the letter and gets to know that Hyun Bin loves Jasmine, his daughter.