Curtis Pike and his family are selected to test a new home device: a digital assistant called AIA. AIA observes the family's behaviors and begins to anticipate their needs. And she can – and will – make sure nothing – and no one – gets in her family's way.

In the dead of night, a young girl wakes her father, claiming she can’t sleep because her mother is tapping on her bedroom window. He soothes her with a story and a music box, insisting her fears are just dreams. But as the lullaby fades, the tapping return.