What happens when your imaginary friend gets all too real? Emma hasn't seen her sister's family in seven years. After a fate meeting, now Emma is living with them. The relationship with the kids were rocky at first, but after an incident with the housekeeper, Emma is now doing her best to take her place. But the youngest kid, Lilly, makes an imaginary friend named Harly that likes to cause trouble. After a while Emma starts to notice that maybe Harly isn't so imaginary after all. What if he's real, and worse sinister?