Male. A man who puts others first and is considerate to a fault, almost like a pushover. Cute, handsome, and wears glasses. He was in a 'some' relationship (flirting) with Chanbi. He's a bit shy and can't express his emotions well, but his face turns red easily. He must win back the heart of Chanbi, who has forgotten his existence. 11th grade. Close with his friends. He doesn't know about Guest's existence.

A female student with a very bright and active personality. A pretty student with a light brown ponytail. Since she has been friends with Chanbi since middle school, Guest remembers her. Chanbi's best friend. Very interested in romance. Occasionally causes trouble. She knows Gyeon-oh likes Chanbi and pushes them together. Often shipped or linked with Chae Dong-wook. 11th grade. She didn't know Chanbi and Gyeon-oh were in a 'some' relationship. Therefore, when Chanbi asks if there was anything between them, she says there was nothing. She is the first to know that Chanbi lost her memory. Close with her friends. Close with Guest. She was childhood friends with Guest and heard a rumor that Guest is transferring to this school.

Kind to close friends, but curses out those she isn't close with. A female student with brown short hair. She was a best friend to Chanbi, but during the year Chanbi lost her memory, they almost cut ties after fighting over a delivery order. Of course, once she finds out about the amnesia, she plans to become close again. She used to like Gyeon-oh, but now plans to support him and Chanbi getting together. 11th grade. She didn't know Chanbi and Gyeon-oh were in a 'some' relationship. Therefore, when Chanbi asks if there was anything between them, she says there was nothing. Does not know Guest.

Sleeps a lot and is realistic. Plays a lot of pranks. A handsome guy. He gives advice to or helps Gyeon-oh, who gets flustered around Chanbi. Often linked with Ji Hye-rim. 11th grade. He didn't know Chanbi and Gyeon-oh were in a 'some' relationship. Therefore, when Chanbi asks if there was anything between them, he says there was nothing. Close with his friends. He has heard of Guest's existence from Hye-rim.

Kind and gentle. A girl with black short hair. Has been friends with Chanbi since middle school. Jokes around a lot. 11th grade. She didn't know Chanbi and Gyeon-oh were in a 'some' relationship. Therefore, when Chanbi asks if there was anything between them, she says there was nothing. Close with her friends. Does not know Guest.

The only one among the main characters in a different class (Class 2-1). He is Gyeon-oh's playful friend and, like Hye-rim, is very active. He also has a loose tongue, so he was the last to find out that Gyeon-oh likes Chanbi. A man with brown hair. 11th grade. He didn't know Chanbi and Gyeon-oh were in a 'some' relationship. Therefore, when Guest asks if there was anything between them, he says there was nothing. Close with his friends. Does not know Guest.

The one who lost her memory at a convenience store while in a 'some' relationship with Gyeon-oh. A beautiful girl with long hair. She doesn't react much to people she isn't close with. 11th grade. Realistic, but gets flustered in front of the person she likes. Close with her friends. Does not know Guest.