Without a Trace by Ariana Nash

Alexander Kempthorne has one more secret to tell, but it could cost him everything. Including Dom.
The windswept Scottish Highlands.
Everything has changed.
With new names and new lives, Dom and Kempthorne should be living their happy ending, but it’s not over yet.
Kage Mitchell knows they’re alive and he’s discovered the single most devastating secret Kempthorne has yet to tell Dom.
There is no other option. Kage Mitchell must die.
But he’s the least of Kempthorne’s concerns. With their identities revealed, and a war brewing between latents and normals, the shadows are on the rise once again, and an old threat awakens beneath London. A threat that could change latents, and the world, forever.
Kempthorne has spent his whole life running from his past. But now, the past is back, and alone, Kempthorne’s not strong enough to win this fight. When the terrible truth is revealed, will Dom forgive him enough to fight with him?