When Gwen's grandfather disappears from their home in New York City, he leaves a message saying not to worry--but it's hard when Gwen has upcoming violin auditions at Julliard! But then she meets Robert, a fellow musician, and things seem to look up.

At the same time, there are other forces in motion, like the scary great uncle who keeps coming by, and the strange man Gwen sees one day when shopping. Then the even stranger story Robert tells her about what she saw. And finally, the discovery that brings their worlds to a halt, uniting Gwen and Robert in ways neither of them could have foretold.

In this remarkable follow-up to the wildly popular Things Not Seen, Andrew Clements brings readers a multi-layered story all about art, friendship, love, and life.