Lights Out Movie Explanation

Sophie, Maria Bello, went to a mental institution when she was young. She made a friend there called Diana who had a weird skin disorder that made her sensitive to light.

The doctors tried to treat Diana's skin problem. The Doctors tried an experiment on her but she died as a result.

After Diana died she haunted Sophie and lived inside her mind. Diana comes back when Sophie is at her worst mental state.

Diana killed Sophie's previous husband then killed her current husband Paul. Diana wanted to keep Sophie for herself and this is why she killed her husbands.

Because Sophie was depressed and mentally disturbed, she couldn't realize the fact that Diana was an evil ghost. Sophie believed that Diana was a friend. The fact that Sophie didn't take her medications made things worse.

Diana started appearing to Martin and Rebecca who shortly understood what was going on. They tried to turn Sophie's attention to the fact that she is talking to a ghost but she didn't listen.

Sophie realized that Diana is evil and that she can't exist without her. Sophie killed herself to Force Diana to disappear and to save her children.

After Sophie killed herself, Diana couldn't exist because her existence was based on Sophie's soul.