The Guardian's Speaker Volume One. The Guardian's Speaker, #1

Some call it gift. Others, curse. For Líf, her ability to see each person's guardian spirit had always been a double-edged sword. She hated drawing attention to herself, especially by those who thought her mad, and yearned for a quiet life. Her greatest fear was that her siblings might not return from the summer raids. Being at sea terrified her-the surging waves, the rolling motion of a longship, the murky depths below-and yet her society flourished from the wealth brought from war and water.
Líf trusted the gods. She understood all choices were preordained. Her fate was sealed, one that linked her to the animal spirits she so loved. Then a man with flesh of a different color upended her life and her world. He brought with him the warning of an invisible plague that would destroy their race and claimed that he was the only person who could prevent it, for like Líf, he also had an unexplainable gift.
The problem was that he was a slave. And he was not hers to free.