The adventure kicks off when a spy breaks into Professor Bacterio's lab Janfri Topera and makes off with several of his inventions from the T.I.A. headquarters (Técnicos de Investigación Aeroterráquea, “Tía”—a playful spoof of the CIA). On the case, Mortadelo [Benito Pocino] and Filemón [Pepe Viyuela], who work for the T.I.A., are hot on the trail, but Fredy Mazas [Dominique Pinon] decides to beat them to the prize. From the very start, there are tense clashes between the spy, Fredy, and the two agents, with Fredy appearing intent on eliminating Mortadelo and Filemón.
The pursuit plunges the trio into a series of comic and dangerous misadventures. Our heroes end up in prison after inadvertently beating up the local cop, a mishap that only fuels the chaos around them. They manage to slip away, but trouble follows quickly: Filemón's mother [María Isbert] is kidnapped by Fredy and taken to Tirania, tightening the stakes and raising the personal cost of the mission. Amid this turmoil, the spy meets his end in Fredy’s stead as Fredy ingratiates himself with the President, all while Filemón’s mother is subjected to torture. The tension escalates as the protagonists race to avert disaster and rescue those caught in the middle of this political intrigue.
When the heroes finally arrive, a sweeping battle erupts. In the heat of the conflict, Filemón appears to be killed, shocking everyone and testing Mortadelo's resolve. In a desperate turn, Mortadelo sustains a mortal wound, but Filemón intervenes in a moment of hope: he offers Mortadelo a cup of water that proves to be the Holy Grail. Mortadelo drinks, heals rapidly, and, with renewed vigor, counters the adversaries and enacts justice on Fredy. The villain’s schemes crumble under the weight of the duo’s perseverance and cunning.
As the dust settles, Mortadelo and Filemón recover, their mission having achieved its goal. They return home with a sense of closure and relief, having faced deception, danger, and betrayal, yet emerging triumphant and ready to resume their lives. The film closes on a note of perseverance and teamwork, underscored by moments of humor, peril, and unwavering loyalty between the two colleagues.
In the end, the story stays faithful to its zany spirit while offering a longer, more textured look at how a quirky pair can navigate espionage, political intrigue, and personal risk. The dynamic between Mortadelo and Filemón—supported by their allies and tested by betrayal—remains the heart of the adventure, delivering a satisfying resolution that honors the source material and the comedic rhythm that fans expect.
