Famous star instructor Seo Hye-jin works until midnight at the academy like any other day. As she stares at the Hall of Fame in the lobby, Joon-ho's name catches her eye. He is one of her proud boast as she did her best to teach him, and he made it into a prestigious university. At the same time, Joon-ho decides to resign from his company and make a new beginning as a rookie instructor.

Even though Hye-jin tries to dissuade Joon-ho, he already passed the first written exam and is getting ready for the test lecture. Therefore, Hye-jin privately asks Ji-seok to disapprove of him. Meanwhile, Sang-sub, the Korean language teacher at Chanyoung High, makes a declaration that creates huge confusion among the students and academies.

A clandestine endeavour dubbed "Teacher and Student Sally Forth" sparks a covert tutoring session led solely by Hye-jin for Joon-ho. Alone in an office after hours, they exchange determined gazes as they delve into a specialized lesson. Meanwhile, the renowned Director Choi, also known as the White Haired Witch, sets her sights on expanding her academy.

Hye-jin and Joon-ho's optimism for their collaborative lecture fades as they discover only one student has attended their free session. Shocked, Hye-jin collapses emotionally while Joon-ho supports her in regaining composure. They soon learn of a tactic by Choi Sun Academy to dissuade students from considering switching, but the lone attendee might just potentially change the game.

Director Choi Hyung-sun, the White Haired Witch, finds out that Hye-jin and Joon-ho taught the class even though there was only one student. She checks on Si-woo to see if he wants to switch academies and asks about the lecture. After hearing about the lecture, she calls Hye-jin to meet up. Meanwhile, Joon-ho asks Hye-jin not to leave the academy and stay with him for at least a year.

Joon-ho finds out that Hye-jin has been helping him out by taking a loss. He tells her that he'll work on his own, and Hye-jin gets strange feelings from his attitude. Meanwhile, the new class opens, and Director Kim gets in an awkward position because his plan to demote Hye-jin fails. He feels worried about Hye-jin leaving the academy. He calls Hye-jin out to talk about it. And Joon-ho tags along with her.