Nicole released the second concept photo and Teaser video of the new digital single 'Mysterious' on the official SNS on the 2nd. The concept photo released on the day showed Nicole in an elegant pose. In the background, the album name 'Mysterious' and Nicole's English name Nicole' are written, and Nicole has created a luxurious mood with an aura that goes beyond chic and charisma. Nicole, who previously expressed the alluring beauty of black in the first Teaser, showed colorful charms with colorful mini dresses this time. Meanwhile, Nicole's new digital single 'Mysterious' will be released on various online music sites at 6 pm on the 9th day.