Malcolm and his best friend Dandy aren't like other 10-year-old boys. Malcolm would rather avoid his older sister, experiment in his lab, and read his science magazines than play sports.

In one magazine, he comes across an advertisement for an Ecto-Handheld-Automatic-Heat-Sensitive-Laser-Enhanced Specter Detector. Its arrival is the beginning of the boys' new career as Ghost Detectors when they discover a practical-joking poltergeist!