Pirate Sun — Karl Schroeder

Return to Virga, a bubble universe artificially separated from our own future universe, and the setting of Sun of Suns and Queen of Candesce.

Chaison Fanning, the admiral of a fleet of warships, has been captured and imprisoned by his enemies, but is suddenly rescued and set free. He flees through the sky to his home city to confront the ruler who betrayed him. And perhaps even to regain his lovely, powerful, and subversive wife, Venera, who he has not seen since she fled with the key to the artificial sun at the center of Virga, Candesce.

Schroeder sets a whole new standard for hard SF space opera.