Loco is an endangered shellfish found off the coast of southern Chile. Its capture is permitted only a few days each year. Resembling an oyster, loco is renowned for its legendary aphrodisiac qualities and is highly sought after in Japan. Loco also happens to be the Spanish word for crazy - so it is an apt name for a creature that manages to drive an entire village insane. Canuto and Jorge are two con men who return to their hometown of Puerto Gala in order to buy the village's entire catch of loco for a bogus Japanese company. Soon the sleepy town is in a frenzy, with everyone desperate to catch as many loco as they can. The cash is placed in the safety of the town's trusted priest. He tries in vain to maintain some kind of order in his increasingly errant community. Canuto and Jorge plot to steal the money and exchange it with counterfeit bills. In the midst of their own "loco fever," Canuto is swept back into a relationship with his ex-lover Sonia and Jorge has his own new romance to nurture.