Brothers in Arms, written by Lois McMaster Bujold and published in January 1989 by Baen Books, is the fifth published book in the Vorkosigan Saga. It has been republished in the omnibus Miles Errant. For audio books: The Reader's Chair published a version in 2001, read by Michael Hanson and Carol Cowan; Blackstone Audio published one in 2007, read by Grover Gardner.
Peace had broken out all over the planet... Which made it tough to be a mercenary captain. If his enemies would just leave him alone, Miles Naismith decided bitterly, the Dendarii Free Mercenary Fleet would collapse all on its own.
But Miles's enemies plot a more deadly fall.
For some unexplained reason the Dendarii payroll is missing and the orders from the Barrayaran Imperial Command are being delayed by Miles's superior, Captain Galeni. What connects the impeccable insufferable Captain Galeni and the Komarran rebel expatriates on Earth anyway? But the most deadly question of all before Miles is more personal: are Miles's two identities, Admiral Naismith of the Dendarii and Lieutenant Lord Vorkosigan of Barrayar, splitting apart along the lines of his divided loyalties? And who is trying to assassinate which version of him?
When Miles unravels the answers, the complications begin.
Miles and his Dendarii fleet arrived at peaceful old Earth tired, in need of repairs, and short of funds. And they'd spent the last few months fleeing the Cetagandan Empire, which was furious about the recent Dagoola prisoner camp escape. The last thing they needed was more money troubles and more assassination attempts.
In order to try to fix these problems, Admiral Naismith performed his disappearing act and Lieutenant Lord Vorkosigan appeared at the Barrayaran Embassy. Unfortunately, the embassy on Earth was small and away from the main Nexus traffic – as a result, it would take at least ten days for their money problems to be resolved – the request had to be sent to Barrayaran Sector II Headquarters on Tau Ceti. In the meantime, Captain Duv Galeni put Miles onto his staff, directly under Ivan Vorpatril, who was second military attachè for the embassy.
"Ivan, how many four-foot-nine-inch black-haired gray-eyed hunchbacks can there be on this damned planet?"
―Miles is prophetic[src]
Over the next ten days, Miles spent the time performing duties as an embassy officer. Then the first official response to his request for assistance arrived; there was no money, just an order to avail himself of opportunities to acquire diplomatic polish on Earth. He sent again and waited some more; ten more days passed. Unfortunately, his duties as an embassy officer and as Admiral Naismith collided more than once; this put his cover at real risk of breaking. At least he had a new romantic relationship with Elli Quinn forming.
At the end of those ten days, another response from Tau Ceti arrived. Still no money, still no mention of the Dendarii. This was enough beyond belief that Miles sent Elena Bothari-Jesek to Tau Ceti to get explanations in person. Also, Galeni promptly disappeared. Clearly, he must have run off with the Dendarii's money. Meanwhile, Miles's two roles collided some more; enough for a group of Komarran terrorists to figure out that he was really both people. This group was headed by Galeni's thought-to-be-dead father Ser Galen, and he had a bizarre replace-Miles-with-a-clone scheme in place and ready to go. They made use of their knowledge of his identities by asking Admiral Naismith to kidnap Lord Vorkosigan; they succeeded in grabbing Miles and replacing him with their trained-to-be-Miles clone. They then locked Miles in a room with Captain Galeni, periodically interrogating one or the other of them.
"Flesh of my flesh, Ivan." Miles turned his hands over, staring at them. "On some planets, he would be called my brother. On others he might even be called my son, depending on the laws regarding cloning."
―Miles sees a brother or son[src]
About three days later, the Dendarii successfully rescued Miles and Galeni. They returned to the embassy planning to capture the clone only to learn that he'd been detained by the London police. At police headquarters, they learned that he'd been collected by the Komarran group again. They went back to the embassy and got some sleep; upon awakening, they learned that ten days had passed and this time, they had a real answer. Commodore Destang himself, the Sector II commander, had come to Earth to fix the situation. Destang fully intended to kill the clone and Ser Galen; which was an outcome neither Duv Galeni nor Miles wanted.
""Rescue Ivan if you can. Then," Miles took a deep breath, "you can blow the clone's head off or whatever you choose." "What happened to 'my brother right or wrong'?" said Elli."
―Ivan is more a brother than Mark is[src]
Battle then broke out at the Thames Tidal Barrier between four groups: a Cetagandan hit squad gunning for Admiral Naismith; a Barrayaran hit squad gunning for Ser Galen and the clone (who looked just like Admiral Naismith); Miles, Ivan, and Duv Galeni, with the backup of the Dendarii; and the clone and Ser Galen. The Barrayarans and Cetagandans ended up arrested, Ser Galen ended up dead, and the clone was released by Miles into the wilds of Earth with money equal to half a million Barrayaran Marks. Galeni and Ivan were allowed to return to their embassy duties. Miles and his fleet were sent to fight hijackers in Sector IV, and Destang hoped that by the time they arrived back in Sector II, he would have retired.
"So. He knew what Mark was. Maybe it was more important to realize what he was not. Mark was not a duplicate of Miles himself, despite Galen's best efforts. Was not even the brother of an only-child's dreams; Ivan, with whom Miles shared clan, friends, Barrayar, private memories of the ever-receding past, was a hundred times more his brother than Mark could ever be. It was just possible he had under-appreciated Ivan's merits. Botched beginnings could never be replayed, though they could be—Miles glanced down at his legs, seeing in his mind's eye the artificial bones within—repaired. Sometimes."