"Beloved" was written by Gorō Matsui and composed by Lee Jae-jin and Suzuki "Daichi" Hideyuki.

[1] The lyrics begin "Kiken'na kaori.. (危険な香り dangerous scent)", and contain the refrain "Top Secret kimi dake daze".

On the lyrical content, lead singer Lee Hongki explained that the person in the song displayed "the image of the playboy who's good on love affairs and going out with many girls at the same time".

[2][3] Guitarist Choi Jong-hoon compared the sound of "Beloved" to that of the English rock band Muse.

Island held their first performance of "Top Secret" at Mezamashi Live in Odaiba on July 28, 2012.