Diplomatic immunity - Lois McMaster Bujold

A COMEDY OF TERRORS . . . A rich Komarran merchant fleet has been impounded at Graf Station, in distant Quaddiespace, after a bloody incident on the station docks involving a security officer from the convoy's Barrayaran military escort. Lord Miles Vorkosigan of Barrayar and his wife, Lady Ekaterin, have other things on their minds, such as getting home in time to attend the long-awaited births of their first children. But when duty calls in the voice of Barrayar's Emperor Gregor, Miles, Gregor's youngest Imperial Auditor (a special high-level troubleshooter) has no choice but to answer. Waiting on Graf Station are diplomatic snarls, tangled loyalties, old friends, new enemies, racial tensions, lies and deceptions, mysterious disappearances, and a lethal secret with wider consequences than even Miles anticipates: a race with time for life against death in horrifying new forms. The downside of being a troubleshooter comes when trouble starts shooting back . . .