On a live music radio show, a letter arrives from the 23 years in the past. Through the letter, the first love and friendships of five friends are revealed.
Doh Kyung-soo
Beom-sil
Kim So-hyun
Soo-ok
Yeon Jun-seok
San-dol
David Lee
Gae-deok
Joo Ah-reum
Gil-ja
Park Hae-joon
Min-ho
Kim Ji-ho
Gil-ja
Park Yong-woo
Hyung-joon
