Of Thorn and Thread by Chanda Hahn

Born an empath, I have the power— and burden— of hearing thoughts and feeling emotions of others. Retreating from the world, my only refuge is an ancient tower, but my haven is shattered when an injured man arrives with a plea to save the kingdom.
Liam is the perfect knight, yet one attribute makes me hesitate. He is immune to my powers. His thoughts are a mystery, his heart an enigma. And while I fear the unknown, I cannot resist the desire to unravel his secrets.
For I am Aura, one of the adopted daughters of Lady Eville. I have joined Liam in his quest to destroy a magical blight that ushers in darkness and poisonous thorns. The closer I get to the source, the more I sense threads of destiny weaving a deadly cage, and at the end of the journey lies a fate worse than death.
Eternal slumber.