Hee-soo, a 18-year-long “never-dated” individual, ironically happens to be the school's top relationship counselor. Secretly, Hee-soo has been harboring feelings for his best friend of 10 years, Joo Chan-young. With zero chance of success, he had decided not to confess and to nurture his bittersweet unrequited love alone. However, someone anonymously identifying themselves as “Carrot” begins expressing their affection toward Hee-soo. "Could this possibly be Joo Chan-young? Does he like me too?" Hee-soo's mind becomes increasingly complicated by these unknown declarations of love.

Seung-won, who secretly loves Hee-soo, devises a fake crush to get closer to him by requesting relationship advice. Meanwhile, Chan-young, who has only been in meaningless relationships, starts developing feelings for Ji-yoo, a girl he meets at the academy. Watching Chan-young's growing interest in Ji-yoo, Hee-soo begins to feel a sense of urgency. Misled by Seung-won’s fake crush, Hee-soo mistakenly believes Seung-won also likes Ji-yoo. This misunderstanding leads Hee-soo to try to bring Seung-won and Ji-yoo together, all while planning to keep Chan-young for himself.