Humanity, divided into a proletariat of Arbites and a ruling class of Adelmen, is dependent for passage between the stars upon the ships of the alien Albenareth. When a bomb destroys the vessel taking them to the planet Belben, the Adelman Giles finds himself with two Albenareth officers and a motley crew of Arbites to contend with. Dealing with the aliens requires all of Giles' intelligence, and the Arbites prove to be more than the childlike dependents Giles expects. In fact, at least one is an operative of a revolutionary organization. Giles triumphs over both alien thought processes and human conspiracy to land the ship on a planet that turns out to be an unsafe harbor. No surprises here--just intelligent SF from two of the genre's pros.