Secrets of Greymoor — Clara Gillow Clark

NO ONE EVER TALKS about Hattie's grandfather, who's been hidden in the Utica Insane Asylum ever since he started hearing voices in the walls. And no one ever talks about Grandmother's fortune, which was squandered away by Grandfather long ago. But after Grandfather's death, Hattie intercepts a threatening notice from the tax collector and realizes that they're in danger of losing everything -- including the family estate.

The discovery of a mysterious book containing a code written by Grandfather leads Hattie to believe that Grandmother's fortune may not be lost after all. Hattie works feverishly to crack the code and restore her family's wealth, but every step forward leads to another riddle. Are the contents of the book simply the ravings of a madman, or is it
possible that there was more to Grandfather than met the eye?