The movie is directed by Oscar winner Chloe Zhao, who is about the title of beings who have lived in on the secret Earth for 7000 years created by entities called Celestials Eternals with tasks with protecting the Earth from Deviants. They must happen evil counterparts. The almost three minute trailer is set to haunting music and finally reveals a lot of answers. Apparently they were explicitly ordered by the Celestials not to interfere unless Deviants were involved