One thousand years after Earth was destroyed in an unprovoked attack, humanity has emerged victorious from a series of terrible wars to assure its place in the galaxy. But during celebrations on humanity’s new homeworld, the legendary Captain Pantillo of the battle carrier Phoenix is court-martialed then killed, and his deputy, Lieutenant Commander Erik Debogande, the heir to humanity’s most powerful industrial family, is framed for his murder.

Crossover is the first novel in a series which follows the adventures of Cassandra Kresnov, an artificial person, or android, created by the League, one side of an interstellar war against the more powerful, conservative Federation. Cassandra is an experimental design - more intelligent, more creative, and far more dangerous than any that have preceded her. But with her intellect come questions, and a moral awakening. She deserts the League and heads incognito into the space of her former enemy, the Federation, in search of a new life.

Sixteen-year old Hazel lives in the Daedalus, a starship that is flying in search of a new world. The ship has been traveling for 500 years, searching for a world to settle in after having to abandon its last world. Everyone on board Daedalus lives a very simple existence in farming villages. The age of machines supplying their needs was lost during a mutiny 500 years ago. 

During a test flight for the world’s first warp engine, Major Noah Gantz is set to go down in the history books. Despite years of training, the mission goes sideways, and instead of a quick trip to the moon and back, Noah's ship is transported across the universe to stars unknown.

For centuries, mankind has searched for nonhuman civilizations in the cosmos. These lost alien societies have finally been discovered—but they were destroyed long ago. Devin Starn starts off as a lowly rock rat aboard Borag, a mining ship working the dangerous end of the asteroid belt. Slowly, he gains prestige and purpose. When an alien base is uncovered, however, he must risk everything to protect his ship and her crew. What wiped out all the civilizations that came before humanity?