The battle at the galactic center had been a great victory for the Federation and the Alliance but at a tremendous cost. The Battleship Avenger and her fleets had vanished being drawn into a great white vortex at the moment of victory. For over four years, the mystery of what happened to the Avenger has haunted the Federation.

The last two survivors of the Special Five have built a powerful exploration cruiser to go off in search of the lost fleets. They are convinced that the fleets have survived and are trapped in another galaxy. What they find in their search will be a threat to the Federation far greater than the AIs and the Hocklyns had ever been. The fate of thousands of worlds will depend on the Distant Horizon finding those that were lost and stopping this new and dangerous menace.

In former Hocklyn space, the Borzon and the Shari are on the move. Their fleets are seizing large areas to add to their own Slave Empires. Admiral Race Tolsen and Third Fleet are sent to push the Borzon and Shari back to ensure the recently freed worlds don't once more fall into slavery. Unknown to Admiral Tolsen is the fact that he has an important role to play in the survival of the lost fleets, as well as the galaxy.