It’s the ninth installment in The Conjuring Universe. Based on the real-life Smurl haunting case. Ed and Lorraine Warren return as paranormal investigators. The story begins in 1964 with the Warrens investigating a haunted mirror. 

Lorraine has visions, gives birth under frightening circumstances. Decades later, a family (the Smurls) moves into a house that has a mirror. The supernatural events escalate, involving multiple entities. Eventually, the Warrens try to help.