The Warmth of Other Suns By Isabel Wilkerson

Born ​in the firelit domain of the under realm, Matilda is the youngest goddess of her clan, blessed with humble messenger magic. But in a land where gods often kill each other to steal power and alliances break as quickly as they are forged, Matilda must come of age sooner than most. She may be known to carry words and letters through the realms, but she holds a secret she must hide from even her dearest of allies to ensure her survival. And to complicate matters . . . there is a mortal boy who dreams of her, despite the fact they have never met in the waking world.

Ten years ago, Vincent of Beckett wrote to Matilda on the darkest night of his life―begging the goddess he befriended in dreams to help him. When his request went unanswered, Vincent moved on, becoming the hardened, irreverent lord of the river who has long forgotten Matilda. That is, until she comes tumbling into his bedroom window with a letter for him.

As Fate would have it, Matilda and Vincent were destined to find each other beyond dreams. There may be a chance for Matilda to rewrite the blood-soaked ways of the gods, but at immense sacrifice. She will have to face something she fears even more than losing her magic: to be vulnerable, and to allow herself to finally be loved.