It revolves around two people: a genius mathematician with a hidden past and a student who is failing math.

[4] A genius mathematician, Lee Hak-sung, defects from North Korea in pursuit of academic freedom.

To conceal his identity and past, he takes on the role of a security guard at an elite private high school, where only the top 1% of gifted students are admitted.

However, his life takes an unexpected turn when he meets Han Ji-woo, a struggling high school student who has given up on math.

As Hak-sung teaches Ji-woo not just how to find the right answers, but how to navigate the process of problem-solving, both of them experience an unexpected transformation in their lives.