Though determined to stay retired from the counter-espionage agency known as ICE, Matt Helm (Dean Martin) is tapped by MacDonald, his former boss, to find a hijacked American spacecraft that, in the wrong hands, could be used to control the world. Just the kind of "wrong hands" MacDonald and his superiors feared, Jose Ortega (Albert Salmi) and his Acapulco beer-brewing associate, Quintana, will stop at nothing short of global domination. So, armed with a collection of state-of-the-art secret weapons, Helm leaves behind an incredible bachelor apartment and a very private secretary, Lovely Kravezit, for the Mexican Riviera. In Acapulco, Matt not only tangles with double agent Francesca Madeiros (Senta Berger), but also with the equally lovely pilot of the stolen spacecraft, Sheila Sommers (Janice Rule). All too aware of the growing sexual tension between them, Sheila jealously watches Matt react to Francesca's seductive charms, the many beautiful girls surrounding Quintana, and twelve "Slay-girls" who seem to pop up at the most awkward moments. To smash the Ortega-Quintana operation, Matt must first escape death by firing squad and survive a running battle in Ortega's brewery. And when he and Sheila finally recover the spacecraft, the "Ace from ICE" and his "out of this world" girl are free to pursue their own brand of romance.