Protecting You by Robin Patchen

In a high-stakes game of deception, two rivals must work together to bring down a ruthless terrorist.

After Alyssa’s dream of working in US intelligence is thwarted, she leaves her mundane profession to pursue a career as a cyber investigator. Though she aces every case she gets, securing enough customers to stay afloat proves challenging. When a lucrative commission comes along, she thinks she’s hit the jackpot. But this client isn’t the British entrepreneur he claims to be. And then her old nemesis interrupts their meeting with a startling move.
CIA agent Callan Templeton is floundering in his new role as a single father to a surprise daughter, but he still has a job to do. He follows a tip about a terrorist, only to be shocked when he finds his old college adversary dining with the notorious killer. Maybe there was a better way to step in than by posing as Alyssa’s fiancé, but it was the best excuse he could come up with to insert himself into their meeting.
Callan once stole the job Alyssa coveted, and now the last thing she wants is his help. But when he explains who her client really is, she realizes she’s in way over her head. Dariush Ghazi knew exactly what he was doing when he targeted her. She’s trapped. She must go along with a dangerous scheme, pretending to help him while working with Callan…or end up dead.
In their quest to dismantle Dariush’s network of evil, Callan and Alyssa risk sacrificing each other—and everything they hold dear.
Prepare to dive into this gripping tale of enemies turned allies, a fake engagement, and a deadly conspiracy.