A Ballad of Blackbirds and Betrayal. Dynamis Security, #4

Vengeance burns. Justice demands. Together, they'll bring down an empire. Eight years after his wife's murder and daughter's near-fatal shooting, Atticus Cameron has built Dynamis Security into a covert force that operates in shadows where even government agencies fear to tread. His singular mission: hunting the powerful senator who ordered the hit that destroyed his family. Dr. Sabrina Wells, a brilliant trauma surgeon with a military past, stumbles onto a medical mystery when patients display symptoms of an engineered bioweapon.
Her investigation puts her in the crosshairs of Senator Warren Mitchell-and directly in Atticus's path. As Mitchell prepares to auction his devastating weapon to international terrorists, Atticus and Sabrina form an uneasy alliance. Their race against time transforms into something neither expected-a connection that challenges them both to move beyond their haunted pasts. With a deadly bioweapon threatening thousands and corruption reaching the highest levels of government, they'll need more than tactical expertise to survive.
In this high-stakes thriller where conspiracy meets chemistry, Atticus and Sabrina discover that some bonds are stronger than the wounds that forged them.