A Desolation Called Peace is simpler and better than the first book. A few months after the coup that saw a new emperor, and Mahit returned home, the war against the aliens is going poorly. The enemy has superior drive technology, something which lets their ships disappear into a swirl of visual distortion, and the six legions sent to fight them are being cut apart in a slow battle of attrition. When the fleet finally spot an one of their elusive foes, a ship of three rotating rings emitting horrific noises which cause people to vomit, supreme commander Nine Hibiscus calls for a negotiator from the homeworld.

That negotiator is former diplomatic assistant Three Seagrass, who decides this will be an adventure and a chance to see Mahit again, since the war is just past Lsel Station. Mahit has been dealing with her own political problems at home, with the government trying to decide if she's a loose end to be tied up, or a tool that still has use in advancing their agenda of getting the Empire caught in an endless quagmire of war.

The basic plot is therefore an attempt to make first contact with aliens who don't seem to understand the concept of language, with a race against factions which would prefer to see the negotiation fail. A wounded Empire is a dangerous thing, and even though its outmatched in space, the Empire has plenty of planetkilling nuclear weapons.

The points of view expand to include Nine Hibiscus, fleet commander, and Eight Antidote, the 11 year old heir to the throne, who is precociously working behind the scenes to learn the duty of an emperor and forbid genocide. First contact is pretty standard for scifi, and Martine's aliens are serviceable, but the straightforward scientific puzzle lets her characters shine under stress, where they spent too much of the first book stumbling through someone else's intrigue.