
S01E01 Fermat’s Last Theorem
At Asung High, Yoon Su’s new workplace, she gives a tricky question for students who want to join the math club. While no one in the class got the question right, a correct answer sheet...
Yoon Su starts to smile little by little thanks to Seung Yoo, and the two of them have an enjoyable and memorable time together. Meanwhile, Noh Jung Ah, who is furious at Yoon Su for targeting her, decides to get in the way of Si An, the one student Yoon Su cherishes. Yoon Su notices the provocation and resolves to face her.
A sexual scandal between a math teacher and a student in a prestigious high school ended in tragedy. 4 years later they meet again, now as adults, to reveal the corruptions in school and to regain one's reputation as a teacher.