Photo: Apple TV+ Sydney Sweeney makes her entrance in Echo Valley like an apparition in a horror movie. The movie’s main character, Kate Garretson (Julianne Moore), is the owner of the verdant Echo Valley Farm, where she boards horses and gives riding lessons to the privileged children of Chester County, Pennsylvania. She’s been making a go of things alone since the death of her wife six months earlier, and she’s out working in the stables when her dog suddenly starts barking and rushes outside.