The crew aboard the Stellar Survey Starship Magellan returns to Earth with bad news from their expedition to the Crab Nebula. Out among the stars, a million systems have fallen under the weight of Broan force—a fate awaiting Earth should the Broa learn of the planet's existence. Having received this knowledge, Earth's politicians argue over their next move, confronted by a problem with no acceptable solution.

In the meantime, Mark Rykand and Lisa Arden have embarked on a dangerous mission to spy on this newly discovered, all-powerful enemy. They must gather useful intelligence quickly—if their cover is blown too soon, the extinction of humankind is nearly certain…