In this quiet high school drama, a reserved 10th-grade girl navigates the monotony of her daily routine, keeping to herself while maintaining good grades and playing her instrument. She's an ambivert, choosing when to socialize and when to retreat into her thoughts. But each day, her focus sharpens as she anticipates 7th-period chemistry with Mr. Le, her enigmatic teacher who always wears dark clothes, a mask, and glasses. Drawn to his mysterious demeanor, she silently observes him, intrigued by the distance he maintains from the world. As her curiosity grows, so does her quiet fascination with the man who seems like an unsolved chemical formula.