Assassin's Code

When Joe Ledger and Echo Team rescue a group of American college kids held hostage in Iran, the Iranian government asks them to help find six nuclear bombs planted in the Mideast oil fields.

These stolen weapons lead Joe and Echo Team into hidden vaults of forbidden knowledge, mass murder, betrayal, and a brotherhood of genetically engineered killers with a thirst for blood. Accompanied by the assassin known as Violin, Joe follows a series of clues to find the Book of Shadows, which holds a truth that threatens to shatter his worldview.

The fourth Joe Ledger novel, following The King of Plagues.