A new door has opened, leading to hundreds of doors.

It is your choice to knock on one to open, especially to the door of the one you dear.

Three friends are about to enter the door to the entertainment industry that will welcome them with problems involving hardships, friendships, families, and love. Three doors will open and three stories will begin, with some meddling people blocking along their way, including the boys they hold special in their hearts. Will they ignore their door to pursue the door of their ambitions or will they knock their door to pursue to their hearts?

[MAIN CHARACTERS]

KNK

Kim Youjin | Park Seungjun | Oh Heejun | Jeong Inseong | Kim Jihun

YNB GIRLS

Bae Seulri | Jeong Danah | Lee Yeonhee