12-year-old Archie Wiggins is intrigued when a new family moves into the big, spooky house next door. The young girl and her parents seem to be strange and secretive and able to do things which shouldnt be possible. Archie witnesses the girl, dressed all in black, performing a magic trick in her garden. Except that he doesnt believe that its a trick; he convinces himself that what she is doing is real magic and that she must be a witch.
Archie sets out to prove this but he soon realizes that getting involved with the Girl in Black will lead him into a world of terrifying situations