Speed of Light by Amber Kizer

Fans will be thrilled with the up and coming book in the Meridian trilogy as the romance between Meridian and Tens heats up. And Juliet returns, but her obsessions leave her open to evil exploitation.

Meridian Sozu is a Fenestra, an angel infused human, destined to transition souls into the next world. Together with Tens Valdes, her soulmate and Protector, they've made a home in Indiana, making sure the dead safely enter the light and aren't stolen by the Dark, known as the Nocti.

Upon rescuing Juliet Ambrose from her terrible childhood, Juliet has become vulnerable without her Protector and grasps at any hope to find her parents, even when it's offered by a proven Nocti, Ms. Asura. Juliet is now faced with the horrible choice between uncovering her past and having a future.

Meanwhile, time may be running out for the hundreds of thousands preparing for the festivities surrounding the Indianapolis 500 car race. As centuries of secrets are revealed, the battles will pit Light versus Dark. Not all with survive as Meridian, Tens, and Julie join forces to try to thwart a potential tragedy.
 
- Goodreads Summary