Book #3 in the Popchuck Chronicles series by Paul Toffanello.

Popchuck’s End brings history to life when Neil leads his friends on a trip to Salem, site of the infamous 1692 witch trails and the topic of their award-winning school project. Ally thinks she sees an ancient ancestor at a tourist attraction. Neil tries to track down a malevolent witch who has been stalking him since he left home and Adam considers putting his vacation brochures aside long enough to help defeat an evil plot against the entire human race! This is definitely not a good time for Popchuck’s ghost to go missing.