Tzuyu is a simple, shy, smart and popular in her school along with her best friend Yeri. She never misbehave and never take advantage using her popularity unlike other girls in her school.

Her parents sent her to Seoul (she is from Busan) to study when she was just 13 (she stays with a maid and later yeri moved in). Mr & Mrs Chou had a hard time to convince Tzuyu to live without them because they always go around other countries for business purposes, so they thought Seoul would be good for schooling. Nayeon, (4 years older than Tzuyu) she stayed back in Busan as she is stubborn but she failed to stop their parents from sending Tzuyu because Nayeon was told that it's for the better future for Tzuyu. She agreed thinking about her sister's future as she loves Tzuyu.

Before Tzuyu left for Seoul, she made her parents to promise her to bring her back to Busan as soon as she graduates from high school because she grew up in Busan and all of her friends (twice) are there.

Yugyeom, on the other hand, is a handsome guy who is very popular with girls and maintains a shy and calm image on the school campus. He, actually is a spoiled guy (tho he is good at heart). He dates a lot of girls from different schools, he believes that he is fulfilling the girls dream to date him.

Jungkook, he grew up with his hyung (Jin) in Busan. Jungkook was 8 years old and Jin was 13 when their mother had an accident and died after been in coma for 1 and half year. Few years later when he turned 13 and Jin turned 18 years, his dad abandoned them and got married to a woman. 

After these incidents, Jin promised to himself that he won't let these things affect Jungkook's life. As time flies, Jin turned cold and couldn't make himself trust anyone besides Jungkook. 

Jin goes to an university and also work many part time jobs to support both of them, as for Jungkook he stays in a boarding school. But later he was forced to transfer in different school because Jin couldn't afford. 

Jungkook is the only family of him and also Jin is the only family of Jungkook.