This Is Not a Drill

"Two teens try to save a class of first-graders from a gun-wielding soldier suffering from PTSD.

When high school seniors Emery and Jake are taken hostage in the classroom where they tutor, they must work together to calm both the terrified children and the gunman threatening them–a task made even more difficult by their recent break-up. Brian Stutts, a soldier suffering from post-traumatic stress disorder after serving in Iraq, uses deadly force when he’s denied access to his son because of a custody battle. The children’s fate is in the hands of the two teens, each recovering from great loss, who now must reestablish trust in a relationship damaged by betrayal. Told through Emery and Jake’s alternating viewpoints, this gripping novel features characters teens will identify with and explores the often-hidden damages of war."

Summary from Penguin Random House: https://www.penguinrandomhouse.com/books/311123/this-is-not-a-drill-by-beck-mcdowell/