"Eunbi-unnie! What are you doing today? Are you busy? I'm bored," asked Chaewon, who peeked over her senior's cubicle in front of her. Kim Chaewon was a graduate teaching assistant (TA) for the Physics department of Korea University, and she was bored. The best thing about being a teaching assistant was that outside of grading papers, there was nothing else to do really. Thankfully, she was not given a lecture class that semester since those were given to more experienced TAs like Eunbi. Since it was only Chaewon's second semester as a graduate student and TA, their supervisor thought it wise for her to just grade papers for Eunbi instead.

"I'm always busy, Chaewon. Wait til they assign you to teach a lecture class with 200 students. You won't have any time to goof around and stare at nothing like you're doing right now so enjoy it," answered Eunbi. Eunbi is two years Chaewon's senior in both their graduate studies and in being a TA. Eunbi is a straight A student, which was why she was given her first big lecture class in her second semester. Although it was hard to balance at first, Eunbi managed to maintain her 4.0 GPA while getting good evaluations from her students that semester. The higher-ups in the department decided that Eunbi was capable of handling two large lecture classes in addition to her workload as a student. Needless to say, Eunbi was just trying to keep her head afloat amongst all her responsibilities but it's not like the administration cares.

Chaewon paid no heed to her senior's advice and asked again, "Unnie... You're doing a discussion class today, right?" 

Eunbi nodded in response, "Yeah, that's what we're scheduled to--- wait, why are you so interested in my class recently?" Chaewon felt her face heat up and her brain suddenly shut down, causing her to stare at Eunbi with wide open.

Eunbi slightly frowned and continued, "Last week, you sat in on my lecture because you said that you wanted me to introduce you to the students so that they'll know who to ask when they have questions about their grades. After that day, you have been asking me more about my class and if you could sit in again. Are you that bored? Or is there another reason?"

Chaewon wanted to defend herself, but she couldn't respond to her senior's questions. Her brain was too busy remembering what she saw last week when she sat in Eunbi's class.

FLASHBACK (1 WEEK AGO)

She had just finished grading the the latest quiz for Eunbi's class and she saw that there were a lot of students making the same mistake in one of the problems in the quiz. Chaewon brought it up to Eunbi, but Eunbi said that she had emphasized how a problem like that should be solved in the class. However, being the angel Eunbi was, Eunbi asked Chaewon to grade the question mercifully.

But Chaewon did not want to show mercy,because it was the same problem that caused her to get her first and only A- of her undergraduate life, ruining the chance of her getting a 4.0 GPA upon graduation. Chaewon argued that the approach most students used was fundamentally wrong and they should be deducted more points for their answers.

"Eunbi unnie, I know you all want them to pass but this is not right. In classical mechanics, kinetic energy can NOT be negative! Only the change can be negative!" Chaewon was getting so animated about the problem that Eunbi was left no choice but to agree with Chaewon.

"Fine, but you yourself should go and explain how you graded this problem in front of the class," said Eunbi with a sigh.

"That's fine with me," answered Chaewon. She did not want to be an , but if she got deducted a lot of points for this problem, then Eunbi's students deserve that too.

Chaewon entered the room five minutes before classes started. She looked around and saw the students playing with their phones while waiting for the lecturer. Nothing special, she thought, until someone caught her attention in the far corner of the room. A cute blonde girl was quietly reading the textbook, unlike her scrub classmates who were wasting their time lurking on social media or playing games. Chaewon thought the girl looked Japanese because of her features, but what stood out to her was the work ethic that this girl had.

She is cute AND smart. What more could Chaewon ask for?

Chaewon was too busy staring at the girl that she didn't notice Eunbi walk in and set her things up for the lecture. When Eunbi looked up to the class, she was confused to see Chaewon still standing and apparently looking towards the far side of the room.

"Chaewon, is there something wrong?"

Chaewon was taken out of her trance, and after recognizing her awkward situation, she lets out a shy chuckle and sat down on one of the unoccupied seats.

Yes Eunbi-unnie. Something's wrong.

My heart just got stolen.

END FLASHBACK.

Chaewon finally managed to get words out of , "Fine. I won't ask anymore." Chaewon sat back down in her cubicle and looked for something she could do to pass the time since she still needed to wait four more hours before her graduate class. She started organizing her cubicle when a piece of paper caught her eye.

Chaewon playfully smirked upon reading what was written in the paper and quickly transformed her face back to a poker face. She had found something that would surely make Eunbi agree to what she wanted to do today.

"Oh! Lee Chaeyeon from the Chemistry department is giving a talk today. I might just go there today to pass the time. Do you want to go with me--- Oh wait you have a lecture class never mind," said Chaewon loud enough that Eunbi would hear her monologue. Her tone had a subtle hint of mockery to make sure that Eunbi would take the bait.

As expected, the older was hooked in by the mere mention of the chemist. Eunbi quickly gathered the papers for her discussion class and walked around to Chaewon's cubicle. She dropped the thick stack of papers in Chaewon's desk and said, "So Chaewon, here is their quiz for today. I trust that you know what to do dur