On-yoo is an adult childhood cancer survivor. When he's not practicing with his boy band, Oh-yoo often volunteers at the hospital's pediatric cancer ward. One day, he recognizes the familiar face of an overdose patient.
| Actor | Role |
|---|---|
 Shim Yi-youngYe-na | Ye-na |
 Im Ji-gyuOn-yoo | On-yoo |
 Uhm Soo-jungSe-young | Se-young |
 Moon ChoiPD Jung | PD Jung |
 Lee Yong-yiNot listed | Not listed |
 Kang Bo-minOn-yoo's sister-in-law | On-yoo's sister-in-law |
 Yang Han-yeolNephew | Nephew |
 Lee Kyung-jinOn-yoo's mother | On-yoo's mother |