Maria O'Malley (Maria II), daughter of a Frenchwoman and an Irish anarchist, is left alone in Central America in 1910 when her father is killed during a revolution.  Skilled in guerrilla tactics, she escapes being captured and joins up with a French circus performer, also named Maria, whose partner in their song-and-dance act has killed herself over an unhappy love affair.  An accident during one of the performances, in which Maria II's skirt tears, turns the act into a successful striptease routine.

As the company passes through the country of San Miguel, the women are horrified at the treatment of the people by the powerful Don Rodriguez.  In anger, Maria II shoots one of the soldiers who are looting a small village.  The troupe is rounded up and taken to Rodriguez' hacienda.  There the Marias meet the revolutionist Florès, who has been captured and tied and bound; and the elder Maria falls in love with Florès.  Florès is shot, but upon his death, Maria I promises to take up his cause.

The two women lead the peasants on attacks on various government strongholds until they are captured and sentenced to death by Father Superior, who is jealous of the women's power.  As both Marias face the firing squad, their colleagues and fellow revolutionaries save them, hailing the women as heroines.