Pournelle, an able and tough-minded science-fiction writer, might have been expected to come up with a good war story. But this is a meager tale about a handful of mercenary soldiers suddenly whisked by the alien Shalnuksis and their still more mysterious human helpers from Africa to an Earthlike planet in a triple star system. Here they learn that they are the latest in a series of shipments from Earth that have been taking place since 1600 B.C. at 600-year intervals; as a result, Tran is a collage of feuding civilizations (Mycenean, Roman, medieval Celtic). Throwing in his lot with the MacClallan Muir of Tamaerthon, Captain Rick Galloway attempts to teach his hosts the elements of military tactics, prepare for the devastating approach of the planet's third sun, and figure out the purposes of the Shalnuksis and their human servants. Pournelle, who ordinarily can do fine things with military whys and wherefores, never really locks horns with these materials except as an excuse for dredging up references to every premodern battle from Pharsalia to Crâ€šcy.