Return of the Emerald Skull (Barnaby Grimes Series #2)

Barnaby Grimes is a tick-tock lad, running errands in his city, day and night, and high-stacking around the rooftops in search of new mysteries to solve. After collecting a strange parcel from a deserted ship in the fog of the docks, and delivering it to the local schoolmaster, Barnaby thinks he's earned a moment to sit on the rooftops and eat his favorite pastry. But soon he realizes that all is not well at the school. Is the problem quite as he expects it? A gruesome tale of a school overrun by a terrible curse—who will survive?