Marie Fitzgerald O'Malley, known as Maria II, is the Irish-born daughter of a deceased Frenchwoman and an Irish republican anarchist who has assisted her father in bombings against the British government from an early age. The role of Maria II is portrayed by Maria Foltyn. While in Central America, Maria II is forced to blow up a bridge on which her father is killed in a shootout with British authorities. The orphaned Maria II escapes capture and seeks refuge in the wagon of Wioletta Chodowicz as Maria I, a French vaudeville performer in a traveling circus troupe.
Together, the two Marias bond and team up for a song-and-dance act called "Maria and Maria", despite Maria II's initial lack of stage experience. During their first performance, Maria II unwittingly invents striptease when her skirt accidentally rips, turning their act into a hugely popular routine.
While touring the country, the troupe is horrified to witness a small village being ransacked by the henchmen of Rodríguez, a powerful landowner, where several innocent villagers are murdered and enslaved. After Maria II intervenes by shooting one of the henchmen, the troupe members are imprisoned and sent to Rodríguez's hacienda along with the villagers. While in jail, Maria I meets Florès, a socialist revolutionary fighting to overthrow the dictatorial government of the fictional Central American country of San Miguel, and they quickly fall in love with each other.
The next morning, Rodríguez arrives at his hacienda and summons the Marias to his office, intending to kill them, but the women seduce him while the troupe orchestrates an escape. As the troupe flees with Florès, he is shot by one of Rodríguez's henchmen. On his deathbed, Florès urges Maria I to promise to carry on his revolutionary cause, and she agrees. Though initially reluctant to acquiesce to Florès' and Maria I's endeavor, Maria II joins the cause when she comes to the aid of her vulnerable friend. After Maria I inadvertently leads her men into an ambush, Maria II employs her bombmaking skills to save them, the two women gathering a peasant army against the forces of Rodríguez, organizing the countryside into a quasi-socialist state.
The Marias' revolutionary activities lead to them becoming venerated like saints, attracting the attention of San Miguel's dictator and the Catholic authorities, who fear the disorder of a revolution and view the townspeople's devotion to the two women as sacrilegious. As they prepare to take the capital city, the Marias are captured by the Father Superior and his churchmen. After a botched attempt by hooded priests to torture them (the Inquisition's equipment is too old to work properly), the Marias are rescued by their victorious army. The dictator, Rodríguez and the Father Superior are all defeated, and the Marias are hailed as revolutionary heroines.
Back in France, the troupe stages a Spanish-language musical retelling of the revolution, with the Marias wearing black wigs.
