Twins Agatha and Sophie one trapped in a glass ball

In 1970s Los Angeles, ignoring the eerie warning of a troubled mother suspected of child endangerment, a social worker and her own young kids are soon drawn into a frightening supernatural realm.

At her family's remote ancestral home, Kelly, her boyfriend, Choppy, and a group of their pals fight boredom by dabbling in a supernatural game called Spirit of the Glass, despite the warnings of a weary caretaker. But once unleashed, the terrifying forces they stir up will not be quieted.