TST will return with a provocative concept beyond maturity.

The music video teaser for the fourth single "COUNTDOWN" was released at noon on December 30.

The TST in the teaser shows unique facial expressions and mysterious moods, showing off even sexy visual beauty, signaling a 180-degree change.

TST, in particular, is expressing its ambition to make a comeback by shouting "COUNTDOWN," which combines with dreamy melodies. 

"COUNTDOWN" is a story that begins with a real life of what one has been searching for in his dreams, and offers a glimpse of the passion that the members have been hiding. 

‘COUNTDOWN’, which features a strong transformation of TST, was available on various music websites on 2 January 2020.