Synopsis - SPOILER ALERT
The action begins as Paul (Billy Burke) is working overtime in a storage hall and is killed by a creepy paranormal creature during the night. His son Martin (Gabriel Bateman) is scared from the same creature called Diana, which apparently talks to his mother Sophie (Maria Bello) in her room. Martin can no longer sleep at night so his step sister Rebecca (Teresa Palmer) decided to bring Martin to her home, because she has already made her experience with Diana when she was young. However, she has problems with the youth welfare office because they do not believe that she can take care of her younger brother, so she had to bring him back to her mothers home. Rebecca and her boyfriend Bret (Alexander DiPersia) try to find out more about Diana. After Rebecca questioned her mother about Diana, she reveals a dark secret about her mothers past.
The director of Lights Out is David F. Sandberg, who also worked on Annabelle: Creation (2017) and Shazam.