After living in a orphanage, Woo Seul-gi transfers to a top-ranking school hoping to find her father - and soon catches the eye of a popular student.

Facing a heartbreaking discovery, Seul-gi struggles to adjust to her demanding schoolwork, while her background makes her a target of bullyng.

Yu Je-i continues to show kindness towards Seul-gi and invites her to her private study space, drawing the two girls closer together.

A furious Choi Gyung becomes suspicious when Je-i nominates Seul-gi as class monitor. Ju Ye-ri overhears a conversation about Je-i's former seatmate.

While Seul-gi finds details of her family history on Je-i's phone, Choi Gyung looks into the connection between the two girls'past.

Students take drastic measures to beat the stress of midterms. Choi Gyung shares a discovery with Seul-gi, causing them to question Je-i's intentions.

Ye-ri makes a deal with Je-i's father, Yu Tae-jun, by using his secret against him. Seul-gi worries about a healt checkup following her exams.

Ye-ri steals Seul-gi's father's phone. As she tries to unlock it, the rest of the students head to the school festival.

An attack at the festival causes panic at the school. Je-i comes to face with a figure from her past as they fight over the stolen cellphone.

As the police investigate the school's drug problem, Seul-gi comes under suspicion. Je-i makes a deal while seeking to help Seul-gi.

Struggling to find Yu Je-na, Je-i decides to frame her for dealing, hoping the police will be able to locate her before their father does.

A traumatic discovery leaves Je-i in a vulnerable state. Feeling uncertain over the situation, a suspicious Seul-gi looks for answers.

While attending a funeral, Seul-gi suspects foul play. Her search foe evidence leads to a grim connection between her father and Tae-jun.

Je-i and Seul-gi take drastic steps when their ranks slide after a big test. Byeong-jin pressures Choi Gyung into taking pills to maintain her grades.

Leading up to the exam, Je-i and Seul-gi craft a final, defiant plan - but there are high risks for everyone involved.