A novella. Originally published in Analog in 1989.
While being a space-faring empire, Barrayar still harbors deep-rooted prejudices and superstitions, including those against "mutants."
When a Dendarii hill-woman comes before Aral Vorkosigan seeking justice for the murder of her infant baby who has been killed because of her physical defects, the Barrayaran Lord sends his son Miles to a remote mountain village to discover the truth and carry out Imperial justice and at the same time attack these long-held barbaric beliefs.
And who better than Miles Vorkosigan, who has himself struggled with these prejudices all his life because of his own physical deformities.
The Mountains of Mourning is a stand-alone novella that takes place (chronologically) between the events relayed in The Warrior's Apprentice and The Vor Game. It won both the Hugo and the Nebula awards the year it was published, as well as an SF Chronicles Award for best Novella.
Lois McMaster Bujold (born 1949) is an American speculative fiction writer. She is one of the most acclaimed writers in her field, having won the Hugo Award for best novel four times, matching Robert A. Heinlein's record, not counting his Retro Hugo. Her novella "The Mountains of Mourning" won both the Hugo Award and Nebula Award. In the fantasy genre, The Curse of Chalion won the Mythopoeic Award for Adult Literature and was nominated for the 2002 World Fantasy Award for best novel, and both her fourth Hugo Award and second Nebula Award were for Paladin of Souls. In 2011 she was awarded the Skylark Award. In 2013 she was awarded the Forry Award. In 2017 she won a Hugo Award for Best Series, for the Vorkosigan Saga.
The bulk of Bujold's works comprises three separate book series: the Vorkosigan Saga, the Chalion Series, and the Sharing Knife series.