Lynn Poole points out that science is often used in crime detection, as when Johns Hopkins physicist Robert W. Wood used ultra violet light to help police solve such crimes as the "candy box murder." Lieutenant Nelligan, Director of the Baltimore City Crime Lab, says that a criminalist, or scientific crime detective, requires a background in both science and police techniques. A dramatization follows the investigation of a fictitious crime, a burglary in a suburban house, to demonstrate the basic tools used to solve the crime: a microscope to match hairs and fibers, a spectrograph to analyze metals and glass, a vacuum cleaner to pick up evidence in a special filter, and a magnifying glass to enlarge details. The density gradient test is also demonstrated and explained. The cast for the scene is from Baltimore's Hilltop Theater: Caddell Burroughs, Elaine Swann, Earl Simmons, John Holland, Alex Quiroga, and Buff Shurr.

Two seemingly unrelated crimes are linked and subsequently solved through forensic techniques involving spectrometry, blood typing, and ballistics with the use of microscopic methods.