Twelve-year-old Diddly Duggins would rather draw than learn about the B-O-R-I-N-G Great Memory Misplacement. No memories of dead loved ones, no grief-who cares?

But that changes when the woman who raised him suddenly dies and he can't remember anything about her but her face and name.

Diddly wants his memories back, and that means figuring out where they went. So when a tree-traveling stumpjumper named Runduncklety Snippet shows up and reveals that he too is on the hunt for lost memories, Diddly decides to go with him to the Spinney, the stumpjumpers' home, where books can walk and sunshine tastes like honey and maple syrup.

Yet Diddly quickly discovers that the Spinney is anything but safe, and he and Runduncklety are soon forced to flee into the wider world-a world of marching trees, feisty fairy-tale creatures, a musical raccoon, and a colossal prison for millions upon millions of forgotten souls...

...souls who will never be remembered unless Diddly can find a way to set them free.