Original member Hyuna left the group two months before the album was released and was replaced by Yubin.

The same month, their debut EP The Wonder Begins was released which featured the follow-up singles "Bad Boy" and "It's Not Love".

The album was promoted with various live performances, including a guest-performance at the 2007 spring festival of the Hanyang University.

The second single from the album was "This Fool (이 바보)", which debuted on MBC's show Music Core on December 10, 2007.

This song was used to promote the South Korean film Hellcats which features Wonder Girls member Ahn Sohee.