This is Mad Ista's story, the story of what happened to a relatively minor character in The Curse of Chalion after the curse was broken. Cazaril (who I liked very much) is off-stage, present only in letters, which at first was a disappointment. I quickly grew to like Ista as a character and as a narrative focus, though. She's prickly and doom-ridden and at odds with the gods, but she's very human and much easier for me to relate to than the empty-headed beauties who people many fantasy epics. Ista is quite unromantically real: on encountering and being saved by a fey swordsman (not bad-looking, either) her first priority -- having been riding, hands bound, all night -- is to request some privacy to relieve herself.
Ista embarks on a pilgrimage, which did set me vaguely in mind of the pilgrimage-anthology (a distinctly Chaucerian echo) that Cazaril was reading in the first book. However, the best-laid plans gang oft awry, and soon Ista is the unwilling heroine of an entirely different story. That story's a direct consequence of the wrongness-thinning-resolution in The Curse of Chalion: it couldn't happen without the previous book, and provides a great deal more context on the workings of the curse and the machinations of the gods. There's a truly epic tale in here, and Ista deals with it pragmatically and effectively.
I was a little disappointed with the ending, I confess: Bujold is a romantic at heart and, major plot threads neatly tied, indulges that aspect of the tale. Reviewing the whole book with rose-tinted spectacles, all the ingredients for a classic romance are there (inexplicable attraction, rivalry, the Other Woman) but I do wonder whether a reader less accustomed to the tropes of the romantic novel would have found the conclusion satisfactory or found it an awkward change of pace and focus.
Lovely clear quiet prose, full of heraldic colours (though there are enough duns and greys and mud-colours to set them off). A couple of clumsy tags -- one character is frequently referred to as 'the riding girl', though she does in fact have a name, a 'nationality' and some other features. On the whole, though, a thoroughly pleasant read.
I was surprised to note that this was a Hugo-winner. I don't know what it was up against, but I suspect it may have won simply by being more likeable than the competition.