Mark is one of the most resourceful men alive: smart, cunning and trained in combat and subterfuge with a brilliant talent for information analysis. He is also weighed down by the knowledge that he is a clone of a more famous and more effective military commander: Miles Vorkosigan of Barrayar. Infiltrating the Dendarii mercenaries by posing as his 'brother', Mark embarks on a vengeful attack on the genetic laboratories on Jackson's Whole. This sets in motion a chain of events that will change his life, and that of his brother, forever.
Mirror Dance is, chronologically, the ninth novel in The Vorkosigan Saga and one of the most vitally important in terms of both the metaplot and character. It starts off in a rather traditional way for the series, with a mission for the Dendarii that appears to be straightforward and then rapidly becomes complicated. The difference here is that it is Mark who has set up the mission and it becomes painfully obvious that, for all his gifts, he is not Miles. Bujold plays a clever game here, since it would be implausible for the Dendarii (who know that Miles has a clone) to fall for Mark's deception so easily, so she has to set up a situation where they would plausibly go along with the plan in any case. Some dangling plot elements established as long ago as The Warrior's Apprentice are exploited ingeniously to do this.
The book opens with a structure that reflects the book's title. Chapters alternate between Mark trying to pull off his crazy scheme and Miles getting wind of it and trying to stop him. Events collide on Jackson's Whole, at which point the story takes a left-field turn that I don't think many readers were expecting. The scale of the book suddenly explodes, incorporating a return to Barryar, our first encounter with Aral and Cordelia Vorkosigan for many novels and some expert commentary on the changing state of Barrayaran society. Then there is a sprint for the finish, taking in explosive action sequences and an extraordinarily disturbing torture sequence that might even make Scott Bakker flinch (okay, probably not).
Mirror Dance is certainly the most epic book in the series to date, revisiting past plot points, characters and events on a scale not before seen (contributing to its unusual length compared to the previous volumes). But Bujold maintains a tight reign on the narrative and backs up the expanded canvas with some impressively nuanced character development. Around for the opening and finale, Miles sits out a large chunk of the novel as Bujold explores Mark's character in impressive depth. Even more remarkably, Bujold uses Mark to develop Miles and his shifting cover identities despite him not being around for a good third of the novel, and also to catch up on some characters we haven't seen for a while.
There's also the feeling of change in this book. The political situation on Barrayar, simmering in the background of many volumes, feels like it is now coming to a head with events in this novel confirming that the new generation - that of Gregor, Miles, Elena and Ivan - is coming into its own. The events of this novel seem to shake Miles's position as commander of the Dendarii, whilst the explosive changes on Jackson's Whole could reverberate across the galaxy. There's a feeling of Bujold loosening things up in this book, essential for any long-running series, and ensuring that readers will want to proceed into this book's direct sequel, Memory, immediately.
Mirror Dance (*****) is a remarkable book and easily the best in the series to date, more than deserving of its Hugo Award. It starts as another military SF adventure, turns into a combination of mystery and political thriller and then skews briefly into action overdrive before concluding with a bleak moment of horror that - apparently - is turned into a positive outcome. Bujold's enviable skills with writing and character make it all seem natural. The novel is available now as part of the Miles Errant omnibus (UK, USA).