Chul-soo is a man with an intellectual disability. One day, Chul-soo finds out that a young girl, Saet-byul, who is in hospital is his daughter. And soon, Saet-byul sneaks out of the hospital and travels by herself to a faraway city for her friend's birthday. As Chul-soo accompanies Saet-byul's journey, friendship develops between the two.
| Actor | Role |
|---|---|
 Cha Seung-wonCheol-su | Cheol-su |
 Um Chae-youngSaet-byeol | Saet-byeol |
 Park Hae-joonYeong-su | Yeong-su |
 Kim Hye-okHee-ja | Hee-ja |
 Ahn Kil-kangMr.Kim | Mr.Kim |
 Jeon Hye-binEun-hee | Eun-hee |
 Ryu HanbiMin-jeong | Min-jeong |
 Cho Han-chulDeok-gu | Deok-gu |
 Sung Ji-ruJeong-kwon | Jeong-kwon |
 Kim Beop-raeMr. Yang | Mr. Yang |
 Jung Won-joongFire Marshal | Fire Marshal |
 Shin Hyun-beenHye-yeong | Hye-yeong |
 Ji Su-yeonJi-an | Ji-an |
 Lee Seung-wonDeok-su | Deok-su |
 Oh Tae-kyungKi-seop | Ki-seop |
 Jung Jun-wonChung-sik | Chung-sik |
 Jung Hee-taePoliceman | Policeman |
 An Min-youngHyun-sook | Hyun-sook |
 Hwang Sung-joonUnderling | Underling |
| LLee Seung-yuopSeung-yeop | Seung-yeop |
 Seo Dong-ohGuest | Guest |
 Yoon Byung-heeDeok-chang | Deok-chang |
 So A-rinSat-byeol | Sat-byeol |
 An Seong-wonYoung Patient 1 | Young Patient 1 |
 Joung Young-subCheol-soo | Cheol-soo |
 Kim Bit-na-raeWoman at the Gym | Woman at the Gym |