Amelia, who lost her husband in a car crash on the way to give birth to Samuel, their only child, struggles to cope with her fate as a single mom. Samuel's constant fear of monsters and violent reaction to overcome the fear doesn't help her cause either, which makes her friends become distant. When things can not get any worse, they read a strange book in their house about the 'Babadook' monster that hides in the dark areas of their house. Even Amelia seems to feel the effect of Babadook and desperately tries in vain to destroy the book. The nightmarish experiences the two encounter form the rest of the story.