"Rocket" was originally scheduled to be released on April 18. However, two days before it is released, the Sewol ferry disaster happened on April 16. Sinsadong Hyung and Jannabi, expressing deep condolences to the victims, decided to delay the release of the song. It was a highly complete song with folk rock and reggae beat, adding Queen's music color on it, and the instant-changing genre changes adds to the point of the song. In particular, it has a unique feeling by playing the brass and the piano in a jazz style.