Group INFINITE released the music video of their repackage album title song "Back" on July 21.

INFINITE posted the full-length music video on their official website, drawing media attention.

In the music video posted online, the members of INFINITE show off their action scene. Actress Kim Hyang Ki, who starred in drama "The Queen's Classroom" featured in the music video as Sungkyu's little sister, who is secretly in love with L.

The music video of "Back" carries the story of the INFINITE members rescuing Sungkyu's little sister. Director Lim Sung Kwan, who produced music videos for Block B and Tasty, participated in the making.

INFINITE revealed their comeback performance last week through TV music programs on July 18. Fans responded enthusiastically to INFINITE's powerful choreography and performance. The song recorded #1 on search engines despite the song not yet being released.

Woolim Entertainment stated: "We thank fans for their positive response to "Back." The members of INFINITE stayed up two nights to wrap up the music video, and attended martial arts classes for 2 weeks to master the action."

Meanwhile, INFINITE will release the official track of "Back" on July 22.