As war clouds loom overseas, auto racers from around the world gather at the Bonneville Salt Flats east of Salt Lake City, intent on breaking the land speed record. When Nigel Underhill, a wealthy English motorist, is found dead and his brother Clive disappears, Art Oveson of the Salt Lake City Missing Persons' Bureau is called to investigate. The Underhill family has hired a former Scotland Yard detective to assist in the search, and he and Oveson begin to follow a trail that leads from the Utah desert to the stately homes of London. As the two detectives draw closer to their suspect, Art finds that the murderer has set his sights on a target much closer to home than he had thought possible.