Ten-year-old Malcolm would rather avoid his older sister, experiment in his lab, and read his science magazines than play sports. In one of his magazines, he comes across an advertisement for an Ecto-Handheld-Automatic-Heat-Sensitive-Laser-Enhanced Specter Detector. With that gadget, Malcolm and his best friend Dandy meet ghosts all around their neighborhood. Thus begins the boys' new careers as Ghost Detectors!