Fall and Rise by Lee Bardugo

The capital has fallen. The Darkling rules Ravka. Responsibility for the fate of the country falls on the shoulders of a broken conjurer of the Sun, a disgraced ranger and the miserable remnants of the once great magical army. The bitterness of defeat and painful thoughts about a bleak future undermine their strength, but Alina believes in the best - her spirit is supported by the search for the elusive firebird and the hope that the exiled prince is alive.