They train to be the toughest, the smartest, the most covert operators in the world—they are the Tier One Navy SEALs, led by Lieutenant Commander Keith “Chunk” Redman.

When a former teammate of Chunk’s is killed in a shocking ambush, rumors begin to fly that the Lion of Ramadi, the infamous Iraq War sniper who racked up dozens of American kills, has returned with a mission to target American SEALs. Chunk and his core team—Saw, a skilled and lethal sniper; Riker, who has an uncanny ability to escape death; and Whitney Watts, a former CIA analyst who sees patterns everyone else seems to miss—are mobilized to prosecute the threat.

But this is no ordinary counterattack, because someone posts the details of the hit all over social media, taunting the American SEALs. Worse, the enemy seems prepared to counter all the Tier One’s moves, a dangerous new stage in the war on terror and a troubling sign that whoever is behind the attack is planning something bigger.

Fearing they may have been duped into chasing the wrong target, Chunk and his team embark on a high-stakes cat-and-mouse mission where nothing—and no one—is what they expect. And when their enemy finds a way to strike at the heart of what’s nearest and dearest to them, it will test not only their bonds but also the personal sacrifices they’ve made to keep America safe.