Book #1 in the Popchuck Chronicles series by Paul Toffanello

Ghosts at Summer Camp? 

Boisterous Neil and timid Adam, 12-year-old best friends, head off to Camp McAbre for the first time with distinctively different attitudes. Neil is excited by the thought of several days outdoors with a hundred other kids while Adam hates everything about camp except for the presence of attractive schoolmate Ally. Yet as the days go by, Adam becomes a super camper while Neil is dogged by bad luck that puts him in conflict with the creepy camp director, Charles Atrom. A bit of late night sleuthing leads Adam into a series of abandonned mine tunnels and glimpses of a ghost who may be responsible for Adam’s troubles.