Plot
This is a romantic comedy series about four boys at the ages of 9, 19, 29 and 39 who each confront different challenges in love and work at the cusp of a new decade in their lives.
Cast
Kim Young-kwang
as Kang Jin-gu
Oh Jung-se
as Gu Kwang-soo
Yook Sung-jae
as Kang Min-gu
Choi Ro-woon
as Kang Dong-gu
Kyung Soo-jin
as Ma Se-young
Yoo Da-in
as Joo Da-in
Park Cho-rong
as Han Soo-ah / Bong-sook
Lee Chae-mi
as Jang Baek-ji
Kim Hyun-joon
as Park Jae-bum
Kim Mi-kyeong
as Gu Bok-ja