For years, Abraham Portman has told stories to his grandson Jake about his childhood surviving in World War II, battling monsters and living at a secret home for children in Cairnholm, Wales. According to Abe, the home’s children and their headmistress Miss Alma Peregrine possess paranormal abilities and are known as “Peculiars”. When Jacob turns sixteen, Jake responds to a panicked phone call from Abe, and goes to his house to find him dying with his eyes removed. Abe tells him to go to “the loop of September 3, 1943”. After Abe dies, Jake glimpses a monster exactly like the ones described in Abe’s stories hiding in the forest.
Jake’s parents sign him up for psychiatrist check-ups, and following advice from his psychiatrist, Dr. Golan, and the lead of a letter from Miss Peregrine to Abe, Jake travels to Cairnholm with his father to investigate the children’s home, whereupon he learns that it was destroyed during a Luftwaffe raid. However upon visiting the ruined house, he finds the children there alive and well. They take him through a portal in a cave and he emerges in the year 1943 when the house was still intact. Miss Peregrine greets him and explains that she belongs to a class of female Peculiars called “Ymbrynes” who can shapeshift into birds (in Miss Peregrine’s case, a peregrine falcon) and manipulate time. To avoid persecution, she and the children hide from the outside world in a time loop she created, accessible only to Peculiars and set to September 3, 1943. This time loop allows them to live the same day repeatedly and avoid aging as long as they stay inside of it.