K-pop boy band SF9 returned again after about a year as a full unit on Monday with the group's 12th mini album, “The Piece Of9.”

“It feels good to be back with my group members. I feel at home and we are very satisfied with how this album turned out. I am excited to see what our fans will think about it,” said Rowoon of SF9 at a media showcase held at Yes24 Live Hall in eastern Seoul ahead of the album release.

Rowoon had put a halt to his participation in the band to pursue his acting career.

Seven members -- excluding Youngbin and Inseong who are fulfilling their military duty -- have come back as "special agents" for the new album.

"I wish I could see comments that praise us for pulling off diverse concepts for our albums. We are very satisfied with the secret agent concept this time,” added Rowoon.

“The Piece Of9” comprises six tracks across diverse genres, with lead track “Puzzle” and side tracks “Love Colour,” “New World,” “Fighter,” “Tight” and “Stay With Me.”

“Puzzle” is an R&B pop tune with heavy bass and an addictive hook that accentuates the vocals of the act. It sings of fitting the pieces of a puzzle together to find out the truth about a tragic ending.

“I took part in composing our lead track and I tried to incorporate the unique musical flavors of each of our members,” remarked Zuho.

The band performed “Puzzle” in jet-black slim suits and showed off a restrained sensual performance at the showcase. The dance moves were angular and minimal with point choreography of wavy moves with a hand at the back of the head.

Other bandmates that took part in the production of the album included Jaeyoon with “Stay With Me,” Hwiyoung on the lead track, as well as some side tracks, and Chanhee writing the lyrics to “New World.”

"The track 'Stay With Me' is the first song that I've ever composed and written. I made it thinking of our fans,” said Jaeyoon.

SF9 also performed R&B pop song “Love Colour” on stage during the media showcase.

Their mellow voices matched perfectly with the slow tempo song as they each performed with a mic stand in front of them.

The act debuted in 2016 with the single “Feeling Sensation” and is known for songs like “Good Guy” and “Trauma.”