Friendly Rivalry

After getting lost as a child and growing up in an orphanage, Seul-gi finally finds her father and transfers to Chaehwa Girls’ High School in Seoul.

A set of elite academy practice questions sent by someone—they’re exactly the same as today’s surprise math quiz at school.

Jae-i gives Seul-gi a new school uniform as a gift. Though she was once wary of Jae-i, Seul-gi begins to lower her guard as she sees unexpected sides of her.

After the class president election, Seul-gi grows closer to Jae-i and ends up spending the night at her house, but when she's woken by Jae-i’s phone buzzing nonstop and decides to.

A copy of Seul-gi’s essay, the only one to receive an A+, is found in her classmates’ desks, and while Jae-i gets upset and insists no one read it, Seul-gi, strangely enough.

Disappointed to learn that Jae-i had an ulterior motive for getting close to her, Seul-gi finds herself nearing midterms.

Seul-gi rises to the top of the class alongside Jae-i.

While the school festival is in full swing, Seul-gi decides to give trusting Jae-i another chance. Meanwhile, for some reason, Jae-i is desperate to find Do-hyeok’s phone.

Due to the festival incident, the police arrive at the school to investigate, and Seul-gi, the victim, is ironically accused as the perpetrator.

Seul-gi and Jae-i search for the missing Jae-na. Upon discovering that Jae-na had spoken with Kyung during the festival, Jae-i confronts Kyung.

Jae-i learns that Jae-na had been holding Su-jin's fake ID that Byeong-jin had been looking for. Just then, Jae-i receives a phone call… Jae-na is dead?.

Suspecting the truth behind Jae-na’s death, Seul-gi learns the full story while searching for Su-jin, and begins working together with Jae-i.

Seul-gi and Jae-i try to find Jae-na and bring her as a witness in court. However, when Tae-jun threatens Seul-gi’s life, Jae-i promises to become the daughter her father wants.

During the final exams, the school rankings shift dramatically, and Seul-gi becomes frustrated as she can't figure out Jae-i's intentions.

Seul-gi and Jae-i clash as their plans diverge, and in the end, Jae-i betrays Seul-gi and follows through with her own plan. What was it that Jae-i truly wanted?.