From the Mixed-Up Files of Mrs. Basil E. Frankweiler meets The Apothecary in this time-bending mystery from bestselling author Carol Goodman!

The day Japan bombs Pearl Harbor, four thirteen-year-olds converge at the Metropolitan Museum of Art where an eccentric curator is seeking four uncommonly brave souls to track down the hidden pages of the Kelmsbury Manuscript, an ancient book of Arthurian legends that lies scattered within the museum's collection, and that holds the key to preventing a second attack on American soil.

When Madge, Joe, Kiku, and Walt agree to help, they have no idea that the Kelmsbury is already working its magic on them. But they begin to develop extraordinary powers and experience the feelings of King Arthur, Queen Guinevere, Morgan le Fay, and Lancelot: courage, friendship, love...and betrayal. Are they playing out a legend that's already been lived, over and over, across the ages? Or can the Metropolitans forge their own story?