Diplomatic Immunity recap

Imperial Auditor Miles Vorkosigan is diverted to Graf Station, where a Barrayaran escort has provoked an impoundment while responding to Lieutenant Solian's unexplained disappearance. The inquiry uncovers fabricated blood evidence, a disguised Cetagandan Ba, and a thousand stolen haut fetuses aboard the Idris. Russo Gupta reveals the smuggling trail, while Bel Thorne is found infected by an engineered parasite. The Ba seizes the Idris and threatens Graf with a biological device, but Corbeau aids Miles and Roic in capturing it. The station bomb is contained, and Miles carries the captive, the children, and the evidence to Rosita. Cetagandan treatment saves Miles and Bel, the children are restored, and proof of planted decoys clears Barrayar and averts war. Bel returns to Nicol with lasting injuries, while Miles and Ekaterin reach Vorkosigan House for the safe births of Aral Alexander and Helen Natalia.

Previously: Miles Vorkosigan served Barrayar as an Imperial Auditor after an earlier career under the identity Admiral Naismith with the Dendarii. He married Ekaterin, who is Nikki's mother, and they began building a family together. Miles also has a long history with Bel Thorne, a former Dendarii associate who later became an ImpSec civilian source. As this volume begins, Miles and Ekaterin are on a delayed honeymoon while expecting twins through uterine replicators.

Miles and Ekaterin's delayed honeymoon is interrupted when the Emperor sends Miles to Graf Station as his direct envoy. A Komarran trade fleet and its Barrayaran escort have been impounded after Lieutenant Solian vanished from the Idris and blood identified as his appeared in a cargo bay. Admiral Vorpatril reacted by recalling his force and sending an armed patrol to retrieve the overdue Ensign Corbeau. The patrol fought Graf security, injured Corbeau's quaddie partner Garnet Five, caused a fire, and was captured. At Graf, Miles reunites privately with former Dendarii associate Bel Thorne, now an assistant portmaster and ImpSec observer. Senior Sealer Greenlaw and Chief Venn present the station's case, while Corbeau seeks asylum so he can remain with Garnet Five. Interviews confirm that the retrieval was abusive and that the Barrayaran side bears substantial responsibility for the escalation. Neither Union searches nor shipboard assumptions explain Solian's disappearance, so Miles turns to traffic records, suspicious cargo interests, and the logistics of the apparent blood scene.

The blood attributed to Solian proves to have been synthesized shortly before it was spilled, establishing that the cargo-bay scene was staged. During Miles's inquiries, an apparent Betan cargo handler asks to service hundreds of uterine replicators aboard the Idris. An unknown assailant then fires a modified riveter at Miles, Bel, and the handler, prompting Greenlaw to grant Miles controlled investigative access. In the Idris hold, Miles discovers about a thousand near-term fetuses in unmarked replicators bearing the Cetagandan central gene bank's sigil. The supposed Betan is actually a sexless Cetagandan engineered subject using a false identity, and Miles secretly alerts the Emperor and ImpSec. Evidence from the Rudra's poorly cleaned blood synthesizer ties the false Solian sample to that ship. A web-fingered passenger called Firka had questioned its medtech about blood synthesis and was near events relevant to Solian and the cargo. Miles seeks Firka as a material witness, but Firka and the disguised cargo handler have vanished. Bel also fails to return home, leaving three missing figures and an active attacker at large.

Garnet Five reports that Firka drugged her and Bel after Bel followed him. Workers capture Firka, and identity records reveal him as Russo Gupta, called Guppy, an amphibious former Jacksonian technician using a dead crewmate's name. Gupta admits fabricating the Solian blood trail after warning Solian about a suspicious Cetagandan smuggling operation. He says the passenger Dubauer killed the rest of his former crew after they transported a concealed cargo, while Gupta survived in his water tank. Miles identifies Dubauer as a Cetagandan Ba associated with haut genetic work and believes the Idris contains about a thousand modified haut fetuses. A guard's report places Bel and the Ba aboard the Idris. Searchers find Bel alive but gravely feverish inside a sealed emergency pod, suggesting that the suspected biological weapon is already active. Miles declares a severe biocontamination emergency, cools Bel in ice water, brings in Barrayaran medical volunteers, and moves the Idris away from Graf Station. Recordings then show the Ba leaving in a repair suit, but when the suit is recovered from hiding, it is empty. Graf imposes quarantine while the Ba remains unlocated.

Captain Clogston identifies Bel's illness as an engineered blood-borne parasite that can be slowed by cooling and filtration but not cured aboard the Idris. A trap on the recovered suit infects Miles as well. The Ba takes control of navigation and communications, holds the Idris hostage, demands a jump pilot, and threatens both the ship and Graf Station with a planted biological device. Roic secretly gets Miles into position while Corbeau volunteers as the pilot and uses coded signals to help the captives. Miles infers that the Ba stole the fetal cargo from a Rosita child-ship, creating a risk that Cetaganda will blame Barrayar and go to war. Corbeau opens the way for Miles and Roic, and Roic captures the Ba alive. Bel supplies the likely location of the station bomb, which Graf searchers find and contain among the Minchenko Auditorium's stage lights. Greenlaw releases the fleet, prisoners, replicators, and evidence in return for keeping the contaminated Idris and settling costs later. Miles organizes an urgent convoy to Rosita with Ekaterin, Bel, Gupta, the captive, and the stolen children, hoping Cetaganda can provide a cure and accept proof of Barrayaran innocence.

At Rosita, Cetagandan treatment cures both Miles and Bel after they endure cold stasis during the journey. Ekaterin's messages to haut Pell and Gem General Benin help prevent war, and Benin proves that empty replicators previously found on Barrayar were decoys planted by the Ba. Pell confirms that the Ba murdered the Rosita consort, her attendants, and the child-ship crew, then stole the living fetal cargo in an attempt to establish a new empire around the children. The rescued replicators are formally returned to their haut constellations, and Barrayar and Cetaganda stand down. The cure leaves Miles with circulatory and muscular scarring and greater long-term circulatory risk. Bel has more severe internal damage and may require low or zero gravity while recovering. Bel and Nicol complete an ImpSec debriefing and choose to return to their own life rather than visit Vorkosigan House. Corbeau and Garnet Five have a possible future through Miles's proposal to appoint Corbeau as Barrayaran consul to the Union, but no appointment is recorded. Miles and Ekaterin finally return home, where Aral Alexander and Helen Natalia are born safely from their uterine replicators.

Roic captures the Ba alive aboard the Idris, and Graf Station searchers contain its biological device in the Minchenko Auditorium. Greenlaw releases the Barrayaran force, prisoners, evidence, and stolen replicators in exchange for leaving the contaminated Idris behind and postponing the financial settlement. Miles, Ekaterin, Bel, Gupta, the captive, and the fetal cargo travel to Rosita. Cetagandan treatment cures Miles and Bel, though Miles retains an elevated circulatory risk and Bel suffers more serious damage that may require recovery in low or zero gravity. The stolen children are returned to their haut constellations, and Benin's decoy evidence establishes Barrayaran innocence, ending the threat of war. Corbeau and Garnet Five remain committed to one another, but Miles's proposal to make Corbeau the Barrayaran consul in quaddie space is not confirmed. Bel and Nicol resume their shared life without a recorded resolution of Bel's Union citizenship and ImpSec obligations. Miles and Ekaterin return home, where their twins Aral Alexander and Helen Natalia are born safely.