When cybercriminals hack into the U.S. Marshal's Witness Protection database and auction off personal details to the highest bidder, FBI Agent Sean Nichols begins a high-stakes chase to find the hacker. Trouble is, he has to work with U.S. Marshal Taylor Mills, who knows the secrets of his past, and the seconds are ticking down before someone dies.

It's the intel every agent fears—terrorists have been smuggled into the country, intent on unleashing the most deadly attack since 9/11. With the threat imminent, FBI Agent Kiley Dawson and ICE Agent Evan Bowers are charged with taking down this terrorist cell. The only problem is Kiley blames Evan for the death of her former partner, and she can barely be in a room with him. But with millions of lives on the line, she has no choice. If it wasn't for a bad call Evan made, Kiley's former partner would still be alive, and Evan has to live with that guilt for the rest of his life. When he starts falling for her, the agent's death seems an impossible obstacle—but it's also the last thing he needs to think about. As the terrorist plot targets Kiley's family, the two are pushed to the breaking point in a race to save countless lives.

Just as Homeland Security Agent Addison Leigh reaches the pinnacle of her cyber investigation into a firearms smuggling ring, she's attacked and left for dead. Her estranged husband, ICE Agent Mack Jordan, is notified that she's at the hospital in a coma. He may have let his past military trauma ruin their short marriage, but she never gave up on their relationship, and he remains her next of kin. Mack rushes to her bedside, where he promises to hunt down the man who attacked her. Mack failed her once when he bailed on their marriage, and he's not about to let her down again. But when she wakes up in the hospital, she remembers neither the attack nor ever being married to Mack. And when a second attempt to take her life is made, it's clear something very sinister is going on, and Mack and Addison are in for the ride of their lives.