 Sneak thief Herb Williams steals an oil indicating device containing highly radioactive beryllium pellets and jettisons it in an unsuccessful attempt to avoid capture. A scavenger named Adams finds the device and sells it to a junkyard where Mel (a ham radio operator) buys it for parts. Dan Mathews and the device s handler, Mr. Hoyt, remain a frustrating few steps behind the device despite reluctant assistance from Williams and Adams. Dan asks the American Radio Relay League to warn area radio operators about the device on its evening broadcast. The League does so, but Mel s pregnant wife Ann opens the device and is exposed to the pellets. Dan, Mel, and Mr. Hoyt have only seconds to prevent a tragedy.