A story about Yongsun and Byulyi's new journey of life. 

It's the 1st of December. Soon, it'll be Byulyi's birthday. Lately she's felt this emptiness, as if something was missing. While searching for a way to rid herself of this feeling, she finds mysterious photos of her and 3 women she doesn't recognise.

Four women of different backgrounds embark on a journey to discover themselves. In the midst of a war that is reason for ruin and despair, the elements will be their guides in shedding light onto barren plains.

Jisoo read an article. It was about Jennie and Kai's relationship.

Where Yongsun, Byulyi, Wheein and Hyejin were the closest of friends. But suddenly, Hyejin had to leave in order to continue her studies elsewhere. Unknowingly, she took a piece of someone’s heart with her.    That someone, however, is living a completely separate and different life. 

Years ago, four friends made a promise: to make music diligently so that, one day, they'd be on everybody's lips for their achievements. Now, time has passed them by and the stage, the lights, the smiles and screams have all become part of the path they've blazed together... As they're coming back one more time, shall we shout out for them? You all know the words: "Encore! Encore! Encore!"