In the endless corridors of TIA Headquarters, Mortadelo and Filemón embark on their most important mission yet: finding the missing “Secret Formula” that keeps changing both name and description every chapter. What begins as a simple retrieval from the chaotic filing room spirals into an agency-wide disaster as their efforts inadvertently attract the attention of Fredy the Thief, Pulgarcito the Tiny Terror, and occasionally the villainous Dr. Bacterium.

Through increasingly elaborate disguises (most of which fail catastrophically) and well-meaning interventions from their colleague Bacterio (whose inventions work perfectly until they don't), the bumbling duo creates chaos in every corner of the agency. From the perpetually exploding lab basement to the director's office (which transforms with each visit like a magical disaster), the agents' progress is measured not in successes but in escalating property damage and bureaucratic red tape.

Despite their best efforts (and Mortadelo's 75% disguise failure rate), the formula remains one miscommunication away. Ophelia delivers bad news with professional detachment, the director's blood pressure becomes a plot-critical metric, and the world somehow ends up worse off even when the mission technically succeeds.

Each chapter ends with the formula moving to a new location, Fredy gaining an advantage, and the TIA headquarters resetting like a cartoon universe—all while maintaining the signature visual style of Ibáñez: fast-paced, absurd, and with a touch of that special TIA logic where the most impossible solutions somehow make sense.