Whispers in the Dark (KGI Series #4)

Nathan is being held captive and is in agony. His saving grace is the voice of an angel who eases his pain and helps him regain enough strength to escape. When he does, she leaves him with a void that he can barely stand. When he escapes and returns to the KGI, he hears her again-now she needs him.

Her name is Shae, and she's on the run with her sister. A government group wants to harness their abilities to heal. The KGI wants to help- but can Nathan quiet his soulmate's doubts and convince her that they are meant to face these dangers together?