F.T. Island is only days away from their highly-anticipated comeback!

On December 6 KST, the FNC Entertainment band unveiled their first music video teaser for upcoming single "Unthinkable," the title track off of their 8th mini album 'Lock Up.'  In the clip, the members appear to be in a celebratory mood except for Hongki, who looks sad and deep in thought as he stares off into the distance. The light scratches on his cheekbone indicate he is injured, but he seems too numbed by certain emotions to react to the pain.

Meanwhile, 'Lock Up' is set for release on December 10.

Check out the full teaser above!