A young woman in her 20s, Chae Meehee, visits middle-aged Cho Sungsook and insists that they were once childhood best friends. Though Cho Sungsook has never seen Chae Meehee before, they become closer at Meehee’s insistence. Their pasts cross paths as though they were traveling through time.
| Actor | Role |
|---|---|
 Lee Sang-heeChae Mi-hee | Chae Mi-hee |
| HHong Seung-iCho Seong-sook | Cho Seong-sook |
 Kim Sae-byukHigh school girl / Kim Yoo-young | High school girl / Kim Yoo-young |
 Lee Sun-hoOh Doo-min | Oh Doo-min |
 Im Hyung-kookKim Ik-joo | Kim Ik-joo |
 Lee Joo-youngCho Seong-sook (young) | Cho Seong-sook (young) |
| CChoi Jin-hyeokKim Ik-joo (young) | Kim Ik-joo (young) |
| JJeong WonLee Keun-kyoung | Lee Keun-kyoung |
 Kim Seung-hyunJeong Ui-hyeon | Jeong Ui-hyeon |
| JJeong Kyung-imHouse owner | House owner |
 Na Ju-hoPsychiatrist | Psychiatrist |