Donald Hamilton wrote the engrossing spy book The Ambushers, which was first released in 1963. The exploits of assassin Matt Helm are carried on. Helm does an exacting assassination in the made-up country of Costa Verde in Central America. However, when he finds himself chasing an ex-Nazi named von Sachs, his quest takes an unexpected turn.
Von Sachs is threatening the United States with a nuclear missile that was originally intended for Cuba during the Cuban Missile Crisis. Along the way, Helm works with Vadya, a Russian operative who resurfaces in further adventures of Helm.