Sisters of Sword and Song by Rebecca Ross is a young adult fantasy novel that tells the story of two sisters named Halcyon and Evadne who are forced to go on a risky quest in order to save their country from an approaching conflict. The sisters, who each have their own distinct personalities and motives, take turns narrating the story from different points of view. 

One of the book's central themes is their sisterly bond but I also enjoyed the background romance as it added a layer of emotional depth . The pacing and writing style of Ross are both great, however I think the world-building could have been explored in more detail. Also, it was a bit hard to fully invest in the storylines of several of the side characters since they felt underdeveloped. In general, fantasy fans will probably find "Sisters of Sword and Song" to be a well-written and enjoyable book.