KIM TAEYEON

She is a second-year student of SM High, who lives in room 101 of Soshi Dormitory. She was kicked out of the regular dorms after she choose not to give up a stray dog she found. She can’t resist taking in stray dogs, and she ends up keeping seven of them in her room. As many of the Soshi Dormitory residents have outstanding grades and art skills, she often feels plain and normal among them.

Kim Hyoyeon, the dorm supervisor, chooses her to take care of Jessica Jung, the pet girl referenced in the title, and she is, understandably, reluctant to do so but ends up getting used to it.

Taeyeon decides to become a computer game designer, but her game proposal to a famous computer game company is repeatedly turned down. So, she decides to make a game on her own.

JESSICA JUNG

She is the resident of room 202, as well as a world famous artist who transferred into SM High as a second-year to learn how to draw manga. Although her artwork is widely admired, she knows nothing other than drawing and has an extreme lack of common sense and living ability. Due to this, Taeyeon is forced to “adopt” Jessica and help her out with the basics tasks of everyday life that everyone else takes for granted. She even has to pick out underwear for her to wear or she will go out without them. She has very bad grades, since she cannot pay attention in class, but she can still pass the make-up exams by photographically memorizing all of the answers with her art talent.

TIFFANY HWANG

She’s Taeyeon classmate, who later moves into Soshi Dormitory’s room 203. Although she is harsh to Taeyeon, she actually has a crush on her, and everyone aside from Taeyeon has noticed this. She left her home to become a voice actress without her parents consent, and has to live on her own. After she finds herself low on money, as well as noticing that Taeyeon and Jessica are becoming close, she chooses to move into Soshi Dormitory, which is more affordable than standart student housing. She meets Taeyeon’s mother and earns the latter’s admiration. Taeyeon’s mother even tells her that she would welcome Tiffany as a daughter-in-law.