The United States' most highly classified military weapon, code-named Vigilant, has been stolen from an unmarked Navy ship in the middle of the Atlantic Ocean. Consisting of ninety-seven missiles, each with multiple nuclear warheads housed in a crush-proof capsule, they're to be lowered to undiscoverable locations in the deepest depths of the Atlantic Ocean.

However, before the system is deployed, an unknown group seizes Vigilant, making them the third-largest nuclear power on Earth. Only a handful of people knew about the ship and its route.

Since most were at the highest level of the government's intelligence community and alphabet agencies, the president doesn't trust any of them to investigate what happened. Knowing the threat of Armageddon could be used for political and economic blackmail, he turns to Nemesis, tasking the off-the-books special operations team led by Matti Moretti to find Vigilant at whatever cost.

But as he begins the investigation, Moretti learns that a triple homicide in Prague is connected to the theft, with the investigating detective, Juraj Adamik, holding the key to discovering Archangel, the highly elusive spy believed to be behind what happened. Working together, with the detective focusing on unmasking Archangel while Moretti finds Vigilant, it isn’t long before they discover that those who stole America's newest weapon aren’t their only adversaries.

The CIA and FSB also have reasons for wanting Moretti and Adamik's efforts to be unsuccessful, and each is willing to go to great lengths to protect what neither wants revealed. .