The Splendor of Fire by Ashley Worrell

Left without a voice after being lost at sea, and unable to communicate except with the man she calls Father, Moira Allen has spent her life running wild among the treetops on the Isle of Skye. Observing and sketching everything around her, and assisting Father with the care of “prestigious guests” inside the walls of Cràdh Prison, Moira’s untamed heart and sharp instincts have made her uniquely positioned to change the course of history.
Imprisoned by his brother Niall for disgracing his family and killing his sister Elspeth, Léo MacKinnon has known nothing but a life of loss. First the murder of his parents, then his abandonment in France by his brothers, his wife’s tragic death, and now his imprisonment and separation from his only child. Tragedies all spurred by Léo’s darkest and most painful secret. The secret that no one can ever know, yet it is the secret God will not let him forget.

As the Wolf and the MacKinnons tighten their hold on the Isle of Skye and the Kingdom of the Isles, Léo’s survival lays in the hands of a most unlikely champion—a mute and vibrant beauty who will slip into the heart of his captor, risking her safety, her virtue, and her life, all to ensure the freedom of the man she loves.