[2] It was their first comeback five months after the group's debut.

[3][4] Three songs were recorded for the single album, including title track "Lonely".

[5] J.don was involved in writing the lyrics for all three songs.

[6] The group held a showcase commemorating the release of their single album on October 21.

[4] On October 22, 2015, the group released the single album along with the music video of the title track, "Lonely".