Halcyon - Harbingers, #2

Mirin had let herself believe she'd never need her dagger again. Just be what she seemed, a mild-mannered young wife. But when everything is taken from her--the man she loves, the quiet life she's worked for, her child, her very identity--she knows she has to fight for what's hers, with the  weapons she knows best: The mysterious power of her music. The aid of the fisher bird, the bird called halcyon, harbinger of her god.
And her dagger. Book Two of the Harbingers fantasy series. Can be read stand-alone.