The Graveyard Riddle - Lisa Thompson

Melody Bird has discovered an old abandoned house in the corner of the graveyard, and a mysterious boy hiding out there... Hal tells her that he's a spy-in-training, using the house as a base for his undercover surveillance of a known local criminal. Her friends Matthew and Jake don't believe that a teenager would be entrusted with this mission and turn the tables to spy on him, uncovering secrets and unravelling a mystery as they go.