Hard Night by Jackie Ashenden

It’s their pleasure to serve . . .
Made up of former soldiers, the men of the 11th Hour play by their own rules to protect the innocent, capture the guilty, and stay in fighting shape for whatever–and whoever–comes their way . . .
Jacob Night, ex-Black Ops, owner of a billion-dollar security company, and leader of the 11th Hour, spends his life completing dangerous missions for others. But there’s one personal mission he has yet to complete: Finding his missing brother, who was betrayed by the woman he should have been able to trust. But when he finally tracks down his brother’s ex, there’s one surprise: she can’t remember a thing.
Faith has no memory of who she is. She can’t remember life before she came to work for Jacob Night, and she’s not sure she wants to. But when she and Jacob are ambushed by men who have come to kill her for sins she can’t recall committing, she has no choice but to face the past. Yet once she does, and Jacob’s identity–and her own–come to light, they may not survive with their lives intact, let alone their hearts.