Lethal Echo. The Arsenal, #8

She's spent her life on the periphery of humanity. Bree Geissenger lives by one mantra: You're only as good as your latest creation. Tucked away in laboratories, always wanted for her brains, she's been safe. Unseen. But the new life she has at The Arsenal has upended her carefully constructed world. Unable to cope with the threats against her friends, she fractured. Determined not to be the weakest link, she fled the safety of The Arsenal compound to heal.
Regroup. Hunt. Those she loves will no longer be prey. She'll ferret out everyone who's a threat to those she loves, no matter the cost. There's no sacrifice too great in war. A smart soldier doesn't work alone, though, which means she must work with the operative she wants more than anything. He ran from a past he's swore to never delve into. Ramon Zapata escaped the underground, clandestine world his parents deemed his birthright.
Military life honed him into the weapon he swore to never become and gave him the only true family he's ever known. Life at The Arsenal was everything he'd wanted, including the brilliant, beautiful scientist who blew his world wide open. To save his new family and the woman he loves, he must reconcile his past and work with the black ops organization who spent years hunting him like an animal. Failure isn't an option.
Never quit. Never surrender.