For the young cadets of the famous Space Academy Polaris unit, whose every minute not used studying to become Solar Guard officers is spent on high adventure in space or the distant planets, a month's leave would seem to be a perfect time for rest. But they have other ideas when they plan a trip to the jungles of Venus. There they hope to hunt the most terrifying of all big game—the mighty tyrannosaurus rex!

Their adventure nearly ends before it can even begin, though, when they narrowly escape a time bomb planted on the Polaris. It is clear that someone will stop at nothing to keep them away from the misty planet—but who, and why? Is there any connection to the secretive group who call themselves the Venusian Nationalists?

From remote plantations, to the vast metropolis of Venusport, to the uncharted jungles, Tom, Astro, and Roger face enormous danger from man and nature. The answers they finally discover and how they prevent a war that could very well destroy the Solar Alliance, makes one of the most amazing Tom Corbett stories yet!