Jung-hoon and Si-hoo, both fresh from breakups, make a pact to have nine casual flings. As their encounters continue, their connection intensifies, blurring the lines between friendship and love.
| Actor | Role |
|---|---|
 Yoon Kye-sangJung-hoon | Jung-hoon |
 Han Ye-riSi-hoo | Si-hoo |
 Park Byung-eunJoon-suk | Joon-suk |
 Park Hyo-juJoo-yeon | Joo-yeon |
 Jeong Soo-youngTeacher Kim | Teacher Kim |
 Jo Bok-raeDeok-Rae | Deok-Rae |
 Kim Chang-hwanStudio Part-time Worker | Studio Part-time Worker |
 Kim Eui-sungDoctor | Doctor |
 Jin Sun-kyuCoffee Man | Coffee Man |
 Kim Jae-hwaDol-sook | Dol-sook |
 Han Ji-eunPictorial Model 1 | Pictorial Model 1 |
| PPark Hyun-jiManager | Manager |
 Han Woo-yeolStock | Stock |