After Joplin’s grandfather dies, she finds an old cookie tin in his bedroom. Inside are pieces of a broken antique platter. The fragments are beautifully painted, each part of a bigger scene—a windmill, trees, some geese, a pond, and the face of a girl about Joplin’s age. She gets the platter repaired and hangs it over her bed.
One night, when she is feeling especially lonely, Joplin wishes that the girl in the picture could be her friend. The next morning, a girl very much like the one on the picture appears in the garden behind their apartment. Her name is Sofie and, just as Joplin wished, they quickly become friends.
But Sofie needs help. She’s trapped in a desperate situation, and the only person with the power to release her died four hundred years before. Still, Joplin is determined to try. With the help of a new friend Barrett Browning, Joplin and Sofie struggle to solve an impossible puzzle and outwit a sinister foe who has secret plans of his own.