Invisible sun

The long-awaited final book in Stross' Empire Games series finds the surprises unleashed in Dark State (2018) playing out in unpredictable ways. Helping the Princess of the French Empire defect to the American Commonwealth (AC) hit a snag in the Berlin of this alternate time line, where the United States security people intercepted her handler. Now she is roaming an unfamiliar Berlin. To find her, the AC has enlisted natives of that time line who helped raise Rita Douglas, the daughter of Miriam Burgeson, who is a commissioner of the AC. At this point, it's no surprise that Rita is a double agent, a world-walker who was sent to the AC time line to gather information for the U.S. but is rushed into use by her mother's people to impersonate the princess. The U.S. para-travel agencies are also dealing with an invasion of an abandoned time-line version of Earth by a synthetic-based species that doesn't desire communication, only annihilation. The first flight of the AC's Juggernaut, a para--time travel space vehicle that uses dozens of nuclear explosives maneuver from a dead time line to live time lines, also plays out. How Stross ties everything up is a genuine wonderment and delight.