“Do you want to die?!” seven-year-old Samuel asks his stressed-out single mother, Amelia. She wonders if his question is a threat or a warning. After dealing with Samuel’s frantic tantrums his entire life, Amelia suspects that her son has begun directing his violent misbehavior toward her. However, after a dark and foreboding children’s book called Mister Babadook mysteriously appears on Samuel’s bookshelf, Amelia must decide if her son is truly deranged, or if there really is a bogeyman lurking in their darkened halls at night.