Eight-year-old Jenny (Violet McGraw, The Haunting of Hill House) leads a lonely but imaginative life, surrounded by puppets based on the works of her artist father (Rupert Friend, Homeland). But when her mother (Mamie Gummer, True Detective) is tragically killed in a hit-and-run and her grandfather (Brian Cox, Succession) sues for custody, the puppets and other frightening characters suddenly start coming to life. At first, Jenny is the only person who believes they're real, putting everyone's lives in danger.