High School Musical On Stage! - 우리의 시작을 (Start of Us) (Kang Dongho, Oh Soyeon) (color-coded lyrics) 

A Korean number from "High School Musical on Stage!"(2007), which is based on film "High School Musical"(2006). The musical performance was in 2013, the soundtrack of this version wasn't published. This is for promotion.
Links:
[Kang Dongho, Oh Soyeon - 우리의 시작을 (Start of Us (Start of Something New)) ( • Kang Dong Ho & Oh Soye... )]
[Studio recording/promotion video ( • High School Musical- K... )]