Battletech authors launch a new high-octane, non-stop military epic. An alien race simultaneously slaughters Commonwealth diplomats and command officers while attacking a partially completed Fifth Foreign Legion fortress. The surviving troops try to reach the League's primary base, where they plan to consolidate and attack the aliens (in Book #2).

It was an easy assignment on a peaceful alien world—until the natives attacked! The Sandcastle, on a water world on the fringe of Earth’s expanding empire, houses the Fifth Foreign Legion—troops sent there to protect the interests of Seafarms Interstellar, a powerful Terran corporation. At first, Captain Fraser thought his biggest problem would be keeping the Legionnaires from getting too bored. But that was before the Free Swimmers—the nomadic ocean clans—attacked and nearly overran the Sandcastle. Suddenly, the Fifth Foreign Legion is facing a seemingly unstoppable alien army equipped not only with their native crossbows, but also high-tech offworld weapons that just might spell the end for the Fifth as well as the Seafarms civilians they have sworn to protect.

An outcast after alien invaders strip him of all he holds dear, Wolfgang Hauser, once a pampered aristocrat, flees from his enemies and attempts to piece together his shattered life.