This is a novel that grows on you. When I first read it back in 2005, I reasonably liked it. Except for Cordelia's Honor it was the best part of the saga up till that point in the narrative, but I didn't love it. So I only reread parts of it, but never in its entirety - until now. And boy, this time I absolutely fell in love with it. It has a bit of a slow start (which costs it the half star-reduction), but once the shit hits the fan it's one tour de force of psychology and emotion that keeps you biting your finger nails.
After 2 years, Mark turns up and basically kidnaps the Dendarii posing as Miles for a raid of House Baraputhra's cloning facilities on Jackson's Whole (where he was created as well). Miles races after him and arrives just as the mission fails spectacularly. He ends up shot in the chest and put in a cryotube which then gets lost in the following chaotic retreat. Mark and Elena have the unenviable task of relaying the news to the Vorkosigan parents which means for Elena a return to a difficult past - and for Mark a step into an uncertain future. But the race to recover Miles (dead or alive) isn't over, and Mark won't stop until there's certainty of his clone-brother's fate.
This is Mark's story, who he was, who he is and who he ends up to be. The various roles he has to or chooses to play showcase this, from impersonation, to reluctant and unsure son, to brother and business man - dealing with doubt, guilt, and all the aftereffects that his upbringing with Galen (which is elaborated on here) left him with. Add to that the torture he's put through here, and you get a young man who's somehow toeing the line towards insanity, but nevertheless has never felt more sane and true to himself. It's a veritable tour de force to come to that point, and some chapters are incredibly difficult to read (the black gang's emergence) and make no mistake, Bujold doesn't pull any punches here. This might be the most explicit book in terms of violence and torture against one of her main characters in this saga so far (and overall), and even immoral acts perpetrated by a main character, but it's so rewarding nonethess. Honestly, up till now I've never liked Mark, but in a way Bujold managed to bring him to life in just one (albeit very long) book just as much as she did with Miles. And the Vorkosigan-universe is richer for it.
Miles himself takes the backseat here, but of course he gains a new perspective in life - having an brother, not just a clone, for once not being in the heart of things... and a glimpse of mortality. But his resurrection doesn't come without a price as we'll see. Among all the psychology and character-drama the plot surrounding the Duronas and the despicable machinations on Jackson's Whole get a bit sidelined. But I guess we'll revisit both. Overall, I love the image of reciprocity in this novel: every action has a reaction, just like in the Mirror Dance, a popular dance on Barrayar, and that's transferred to practically everything that's going on here.
Other than Mark himself, the parts that most fascinated me (and the ones that I kept coming back to) are set on Barrayar: the effects Miles' not-quite death has on the Vorkosigans, Mark's introduction into this family, Aral's health crisis which suddenly turns an academic question of succession into a very real one, Cordelia going toe to toe with Simon Illyan, even the small glimpses and huge nudges of Gregor and Kareen Koudelka who both accept Mark for who he is from the start - not just as Miles's clone, but as an individual.
Overall, a stunning novel.