Mystic Story Rookies which are also known as Mystic Story Girls shared the first photo with all members.
Mystic Story Rookies is a 7-member girl group that consists of Miyu, Soomin, Sua, Suhyun, Haram, Tsuki, and Siyoon.
Mystic Story Rookies will debut in the next few months under Mystic Story Entertainment, the subsidiary label of SM. This also means that you shouldn't expect SM or any other SM subsidiary labels to debut other girl groups in 2020.
You can learn more about group members here.
This is Mystic Rookies official IG profile, also all members have their own instagram accounts.
Here are members instagram accounts, and let's praise Mystic Story idea of promoting girls in sns long before debut.