Is Lights Out Scary? The Verdict and the Whole Plot

Closing time at the textile factory

In a textile factory at closing time, an employee named Esther says goodnight to her boss, Paul, and spots a woman's silhouette with claw-like hands. The figure disappears when the lights are on and returns when they are off. Paul sees her too, locks himself in an office and is killed once the lights go out. Not long after, Paul's son Martin catches his mother, Sophie, having a conversation with something in the dark. Then he spots an odd shape in the shadows behind her and locks himself in his bedroom. He starts falling asleep at school, the nurse cannot reach Sophie, and Paul's stepdaughter Rebecca is called in instead. A Child Protective Services agent asks Rebecca about Martin's home life, and she mentions that Sophie takes antidepressants.

Reading this instead of watching it is the correct decision. Scaredy Cat makes that decision automatic, for free.

A name scratched into the floor

Martin tells Rebecca that their mother talks to a woman named Diana. Rebecca says Diana is not real, and that she remembers hearing her mother talk to the same imaginary girl when she was small. At the house, she fights with Sophie, who has stopped taking her medication and says Rebecca abandoned her the way Rebecca's father did. Rebecca takes Martin to her apartment, and that night the shadow woman who killed Paul wakes her and nearly attacks her before the lights go on. The next morning she finds the name Diana scratched into her floor next to a stick figure. She recognizes both from her own childhood and realizes Diana is real.

A girl who could not go outside

In a box of Paul's research, Rebecca finds medical records showing that Sophie was a patient in a mental hospital as a child. There she befriended Diana, who had a skin condition that meant she could not be in the sun. People believed Diana was evil and could get into people's heads, because her father killed himself after she influenced him. Hospital staff then tried an experimental treatment under intense light, and Diana was accidentally turned to ashes. Meanwhile the CPS agent returns Martin to Sophie, who decides to let him meet Diana after turning off the light. Martin is frightened and runs back to Rebecca's place.

Every lamp in the house, including the neighbors'

Rebecca, her boyfriend Bret and Martin confront Sophie about letting Diana haunt the family. Sophie gets angry but then asks Rebecca for help, since Diana will not let her go. The group stays the night and lights the house as brightly as they can, but Diana cuts power to the whole neighborhood. She locks Rebecca and Martin in the basement and goes after Bret, who escapes by shining his car's headlight at her and drives off. Sophie faces Diana to beg her to spare the children, and Diana knocks her out as she reaches for her medicine. In the basement, Rebecca and Martin find a blacklight that lets Rebecca see Diana clearly, though it is not strong enough to keep her away.

Sophie takes the only shot she has

Bret comes back with two police officers, who free Martin and Rebecca from the basement. The officers see Diana's shadow and chase her, and she kills them. Rebecca and Martin get out, but Martin wants Sophie out too, so Rebecca goes back inside alone. This is the scene people dread most, and it happens near the end. On the stairs, Diana tells Rebecca that she killed Rebecca's father years ago for trying to help Sophie, as Paul did. She injures Rebecca and moves in. Sophie, now awake, shows up carrying a dead officer's gun and fires at Diana, which does nothing. Sophie realizes she is the tether that lets Diana exist in the real world, and she turns the gun on herself to save her children. When her body falls, Diana disappears.