Asylum is a New York Times bestselling young adult horror novel series by Madeleine Roux.
The series follows sixteen-year-old Dan Crawford, who was chosen to attend a prestigious college preparatory summer program in New Hampshire.
Once there he befriends two other teens, Abby and Jordan, with whom he explores an old psychiatric hospital that has been re-purposed into a student dormitory.
Dan and his friends have decided to return to the prep school in order to investigate the past summer's mysteries further, especially as someone is sending them creepy old pictures and GPS coordinates to abandoned houses near the Brookline Dorm.
Dan begins to receive messages from someone who died last Halloween and the strange occurrences only escalate once they reach New Orleans.