When an alien scientist is captured by Special Forces soldiers, he reveals a plot to attack all the human outposts - conducted by three alien races, two of whom were previously at war with each other and one of whom is usually relatively non-aggressive. More shocking is the discovery that the ringleader is human.
In an attempt to discover why Charles Boutin turned traitor to his race, and how he plans to commit genocide, the Colonial Defence Forces decide to create a Special Forces soldier with a difference - instead of allowing him to develop his own consciousness they will use a copy of Boutin's, in the hope that this recreation will let them discover this vital information.
Jared Dirac doesn't know why he reached awareness two days later than his squad mates, but although he's a little different he soon fits in, and proves himself to be a dependable and innovative addition to the team. That is until the team take a break on a way station, when Boutin's memories begin to be triggered.
This sequel to Scalzi's fabulous Old Man's War is set in the same universe but utilises different characters and focuses on a different part of the Colonial Defences soldiers. In addition to the genuinely interesting plot and the nuanced character development of Jared, The Ghost Brigades fills out and gives the reader insight into the politics underlying the universe Scalzi's created. For readers of the previous installment there's a little follow up on the story of Jane Sagan and John Perry.
I particularly liked the opening chapter, which gave me an interesting awareness of my own prejudices; the writing is in general good, and I eagerly look forward to reading the (more closely tied to the original) sequel , The Last Colony. - Alex