The Eubians have, in fact, found a way to infiltrate Skolian defenses, a notion strongly hinted in Schism. Mounting simultaneous subtle biological attacks, they incapacitate several members of the Valdoria family at once, and launch a military attack on the ISC home planet and its Legislature. Forewarned by only minutes, the Skolians attempt a massive evacuation, with limited success. The invading fleet is beaten back with heavy losses, but crippling damage has been done. War is declared, but with the severe injuries to several family members, and the destruction of many Kyle gates, the web is unraveling---threatening to destroy the single advantage which has given the Skolians a chance of survival. With Eldrin and Roca both missing, and Kurj bedridden, Sauscony and Eldrinson are pressed into service on the Web, to try and avert disaster.

Further synopsis would probably be too much, as much of the rest of the book is tying up loose ends and concluding various plot lines. But there is one honking great space war. Asaro doesn't try to match Dave Weber in the details of death and destruction in interstellar warfare, but she definitely outpoints him in scale and grandeur: fleets of hundreds of thousands of ships. . .unthinkable casualties in the first seconds of battle.

As in the first episode, The Final Key is as much about the dynamics within the Rhon Valdoria family as the searing events which surround them. These people are nothing if not prolific; yet it is their relationships which drive the plot. But there is far more to appreciate here than the travails of one family. The empire, the society, and the technologies are richly described. An ominous technology is, in fact, key to the events of the novel. The reader will be fascinated when this secret is, finally, unlocked.