Borders of Infinity recap

While recovering on Barrayar, Miles Vorkosigan accounts for three tests of his judgment. In Silvy Vale, he proves that Mara Mattulich murdered Harra Csurik's infant, suspends Mara's death sentence, and gives Harra and Lem a route toward a different life. At Jackson's Hole, Miles's Dendarii mission extracts a Bharaputra geneticist and his gene complexes while freeing Nicol and Taura from rival barons. Taura chooses Dendarii service despite an uncertain medical future. At Dagoola, Miles enters a Cetagandan prison to recover his cousin, then organizes more than ten thousand captives for a mass escape. The cousin dies before rescue, and the evacuation costs at least 206 lives as well as Mirka and Tris's lieutenant. Tris and Oliver survive with a mandate to build Marilacan resistance. Illyan shields Miles from the resulting political attack while Miles begins recovery from his injuries and combat fatigue.

Previously: Miles Vorkosigan serves both as a Barrayaran Imperial officer and as a commander connected to the Dendarii. Illyan, the head of Imperial Security, is his long-standing superior. As this account begins, their established relationship places Miles's covert military work under Barrayaran oversight.

So far: Miles is recovering from major arm surgery when Illyan questions him about politically dangerous irregularities in Dendarii accounts. The inquiry strains their trust. Miles is then sent as Count Vorkosigan's representative to Silvy Vale, where Harra Csurik says her infant daughter was murdered. The medical examination proves that the child died from a deliberately broken neck, not from her correctable facial condition. Harra's husband Lem flees before questioning, while Speaker Karal and the village resist the investigation. After Lem returns and submits to Fast Penta, his account clears him. Miles identifies Harra's mother, Mara Mattulich, as the killer. She admits murdering her granddaughter and two earlier infants, as well as attacking Miles's horse. Miles pronounces a death sentence but suspends it indefinitely, leaving Mara alive while stripping her of property and civil authority under Harra's control. Harra accepts the chance to train as a teacher, Lem may pursue carpentry work, and Miles proposes a school and communications project for the Vale.

Miles explains the expense behind the audit through an earlier Dendarii operation at Jackson's Hole. Acting as Admiral Naismith, he takes the Ariel to extract a senior Bharaputra geneticist. Bel Thorne also agrees to help Nicol, a quaddie musician trapped by Baron Fell's contract. The geneticist refuses to leave without seven gene complexes stored in the last survivor of an engineered super-soldier project, now imprisoned by Baron Ryoval. Miles infiltrates Ryoval's facility, discovers that the supposed specimen is an intelligent sixteen-year-old woman, and names her Taura. Captured beside her, he changes the mission from tissue recovery to a joint escape. Miles and Taura sabotage Ryoval's tissue archive, reject an attempted exchange of Miles for Nicol, and flee with Thorne and the Dendarii. Taura learns why Miles originally sought her and freely permits the biopsy needed to recover the complexes. Miles refuses to return her to Bharaputra control and offers her Dendarii service. Nicol chooses to travel toward her own people, while Taura stays for recruitment. The Ariel escapes after Miles exploits the rival houses' suspicions.

Miles next recounts the Dagoola mission. He enters a force-dome camp holding 10,215 Marilacan prisoners and finds his maternal cousin, the captured Fallow Core commander, alive but catatonic. The camp uses hunger, uncertainty, violence, and remote environmental controls to make prisoners destroy their own cohesion. With Suegar, former sergeant Oliver, and enclave commander Tris, Miles organizes a force that seizes ration deliveries and distributes food evenly. Tris turns the effort into a durable command structure, although Miles's false accusation against a violent faction leader creates a precedent later used against him. The Fallow Core commander dies before rescue. When the dome falls during an external attack, the practiced ration formations become evacuation lines for Tung's fourteen Dendarii shuttles. Elli Quinn and another operative have discovered that the prisoners' skin encodes carry delayed poison, allowing medical teams to remove them. Miles assigns Tris and Oliver to lead a future Marilacan resistance. A Cetagandan fighter destroys one loaded shuttle and one empty shuttle, killing 206. Mirka is shot, and Tris's red-haired lieutenant is lost when a damaged ramp tears away. Miles and the gravely injured Suegar leave on the final shuttle and reach the wormhole.

By the end, all three crises have reached their immediate outcomes. The Silvy Vale murder is solved, Mara Mattulich remains alive under a suspended sentence and Harra's legal control, and Harra and Lem have a possible path away from the village's old pattern. The Jackson's Hole mission recovers the Bharaputra gene complexes and frees Nicol and Taura. Nicol continues toward her own people. Taura becomes a Dendarii sergeant and receives experimental treatment intended to slow her metabolism, though her prognosis remains uncertain. At Dagoola, the prisoners escape under Dendarii protection. A Cetagandan fighter destroys a loaded shuttle and kills 206 people. During the final departure, a sniper kills Mirka, and Tris's lieutenant dies when a damaged ramp tears away. Suegar survives long enough to escape despite critical injuries. Tris and Oliver leave with responsibility for organizing resistance to the Cetagandan occupation of Marilac. Hospitalized on Barrayar with injuries, exhaustion, and delayed combat fatigue, Miles tells Illyan that he would make the same rescue decisions again. Illyan ends the immediate political interference. Elli Quinn remains outside the classified hospital and is expected at the family Lake retreat after Miles's release, where his recovery will continue.

The Dendarii evacuate the Dagoola prisoners after converting the camp's ration organization into orderly shuttle lines and removing lethal poison from their skin encodes. A Cetagandan fighter destroys a loaded shuttle and an empty one, killing 206 people. A sniper kills Mirka during the final departure, and Tris's red-haired lieutenant dies when a damaged ramp tears away. Miles and the critically injured Suegar escape aboard the last shuttle. Tris and Oliver are charged with creating a new Marilacan resistance. Back on Barrayar, Miles defends the decisions and losses to Illyan, who prevents the political critics from disturbing his recovery. Elli Quinn, unable to enter the classified hospital, is expected to join the Vorkosigan family at their Lake retreat after Miles is released. Taura remains a Dendarii sergeant receiving experimental treatment, but her engineered metabolism leaves her future uncertain. Nicol is traveling toward her own people, while the conflict among Fell, Ryoval, and Bharaputra remains unsettled.