Captain Vorpatril's Alliance continues Lois McMaster Bujold's Vorkosigan Saga but includes very little about the series protagonist Miles Vorkosigan. Instead, this book focuses on Miles's cousin Ivan Vorpatril. In previous novels, Ivan was presented as an irresponsible womanizer, sometimes referred to by the insulting moniker "Ivan-You-Idiot". But he is the hero of this story.

When rival houses conspire to overthrow one of the galaxy's royal families, assassins target the family's beautiful daughter Tej and her genetically engineered half-sister, Rish. Fortunately for them, Ivan is ordered by Byerly Vorrutyer of Imperial Security ("ImpSec") to protect them. Ivan rescues the two ladies and hides them from the bounty hunters on their trail; then, thinking quickly during a raid by immigration officials, he marries Tej as a temporary ploy to prevent her arrest, deportation, and likely assassination. The real action starts when they return to Ivan's home planet of Barrayar, where they attempt to annul their marriage of convenience and become involved in clandestine operations that cause conflict between the Barrayaran Empire and others.

This is a romantic comedy that mostly features Ivan and Tej. But we also get Byerly and Rish as a couple, along with Ivan's mother Alys and retired ImpSec chief Simon Ilyan. But it is more than that, as Bujold twists the plot multiple times.

Tej is similar to Ivan in that she is a stabilizing force in a manic royal family. Like Ivan, she lacks the ambition and chaos that drive her relatives.

Everyone assumes that Tej's family is dead until they show up on Ivan's home planet with a secret plan to regain their fortune and their titles.

This was a delightful story that is more lighthearted than most books in the Saga. In the past, Ivan was a minor character, presented mostly as comic relief or as a contrast to Miles's driven nature. Here, we see him fleshed out and struggling with his duties and his feelings. We see his loyalty and his resourcefulness. And we understand why Ivan has always stayed under the radar and appeared to lack ambition.

Bujold's wit takes this story beyond a simple space opera and makes it exciting and fun.