Miss Peregrine, Emma and her peculiar friends are back in Florida with Jacob Portman. They discover a subterranean bunker that belonged to Jacob's grandfather, Abe. Clues to Abe's double life as a peculiar operative start to emerge, revealing secrets long hidden in plain sight. Jacob begins to learn about the dangerous legacy he has inherited - truths that were part of him long before he walked into Miss Peregrine's time loop.

After picking up and leaving everything behind in California, eighteen-year-old Marin, with the help of her former friend, must confront her grief and the truths that caused her to flee her home.