ACE's fourth mini-album 'HJZM: The Butterfly Phantasy', released at 6 pm on September 2nd, is a worldview that constantly challenges by building their own colors with unrivaled concepts through 'UNDER COVER' and 'SAVAGE' last year. It is an album that contains a message to find the true image of ACE, which showed off.

This album, inspired by “胡蝶之夢” by Zhuang Zhou, a classical Chinese literature, contains a total of five tracks, including the title song “Favorite Boys”. The title song' Favorite Boys' is a song that combines intense synth sound and retro house, and contains the message that the public will be reborn as the only ideal type desired by the public in a reality where emotions cannot be fully expressed.