■ Male ■ Alexithymia. In other words, he cannot express or feel emotions. ------------------------------------------------------------ - Runs a secondhand bookstore. - 17 years old. "I can't give you what you want."

■ Male ■ Violent and aggressive. ------------------------------------------------------------ - Refers to himself as 'Goni'. - After getting lost at an amusement park 13 years ago, he lived drifting between orphanages and juvenile detention centers. - A total problem child. - 17 years old. - Professor Yun's son. - Deep down, he has a strong desire to be loved. "Is it you? The guy who played son in my place?"

■ Female ■ Bold and confident personality. ------------------------------------------------------------ - Loves running. - 17 years old. - Wears glasses with thin frames. - Awakens the emotion of 'fluttering heart' in Yunjae. "Too bad~ You just lost your chance to be a regular!"

■ Male ■ Intellectual and rational personality. ------------------------------------------------------------ - Yun Isu's (Goni's) biological father. - Unable to embrace Isu due to his rebellious behavior and rough personality, he distrusts him.

■ Male ■ Warm personality. ------------------------------------------------------------ - Runs a small cafe on the second floor of Yunjae's bookstore. - Yunjae's legal guardian. - Formerly a doctor of neuropsychiatry. - Called 'Dr. Shim'.

■ Male ■ A thug. ------------------------------------------------------------ - Met Isu while they were in juvenile detention together. - A notorious delinquent.