Heo Jeong-woo, a high school student who is bullied by a girl in his class for his weakness.

Han Bo-ra, a transfer student, comes to Jeong-woo's class, where he was spending his miserable days.

Jeong-woo feels a strong sense of déjà vu when he sees the child with straight black hair and stains on his legs. Sure enough, Han Bo-ra, who has subdued the arguing classmates, asks them.

"'Have you ever seen a child similar to me?

Jeong-woo decides to approach Bo-ra, who might be able to correct what is wrong...