"Senseless suicides, senseless crimes. A citywide epidemic. It had hit other cities too. Trimble suspected that it was worldwide, that other nations were simply keeping it quiet." Detective-Lieutenant Gene Trimble has a mystery to solve. "Why would a man like Ambrose Harmon go off a building?" he asks himself. Trimble has already begun questioning numerous other suicides, but Ambrose Harmon's death seemed the most pointless of all.

Harmon had inherited great wealth and had spent it whimsically, without a care in the world. In backing many impractical ventures, he might well have gone bankrupt, but instead he struck gold: a machine that could travel between alternate timelines, retrieving technologies developed in other possible universes. The result was his Crosstime Corporation, and "The Crosstime Corporation already held a score of patents on inventions imported from alternate time tracks." After all, there were "Lasers, oxygen-hydrogen rocket...