The Blackcoat’s Daughter centers on Kat (Kiernan Shipka) and Rose (Lucy Boynton), two girls who are left alone at their prep school Bramford over winter break when their parents mysteriously fail to pick them up. While the girls experience increasingly strange and creepy occurrences at the isolated school, we cross cut to another story—that of Joan (Emma Roberts), a troubled young woman on the road, who, for unknown reasons, is determined to get to Bramford as fast as she can.