At the age of four, Catalina de Erauso, born in the Basque area of Spain in 1585, is placed in a Dominican convent, where she trains until the age of fifteen to become a nun. On March 18, 1600, Catalina runs away from the convent and fashions herself a suit of male clothes out of her convent garments. Thus she begins her life as a man.

She obtains a number of jobs, including one as a page for the king’s secretary. While in his employ, she encounters her father, who is petitioning for help in finding his missing daughter. Her father does not recognize her. She again tempts fate and returns to her old convent for mass, where her mother is in attendance. Catalina’s mother also does not recognize her.

Catalina’s journeys through the New World begin when she meets her uncle, a sea captain who, not recognizing her, signs her on as a ship’s boy. Eventually Catalina flees the ship, stealing money from her uncle as she leaves for Panama, and embarks on a series of jobs and adventures. A number of violent episodes ensue, which often lead Catalina to flee into a local church for safety. At that time, police were barred from invading the sanctity of a church, thus granting criminals inside sanctuary. Catalina’s tendency to get into violent and criminal scrapes leads her to take frequent advantage of this legal loophole.

Catalina also has a number of problematic encounters with young ladies. Some want to marry her, forcing her to ward off their advances. But in one situation, Catalina is dismissed from her position for inappropriate behavior with the sister-in-law of her master. She signs up for the army and soon travels to Chile, where she becomes a soldier for her brother, who does not recognize her. Although they generally get along well, after three years they fight over a woman, and Catalina is banished to another town. She manages to distinguish herself in battle, both for her bravery and for her propensity for violence. She kills many people, both on and off the battlefield, and is constantly running from the law.

When a friend asks her to be his second in a duel, she agrees. During the course of the duel, she kills the other man’s second, who turns out to be her own brother. She retreats to the church to avoid arrest, and from there, wracked with sorrow, she watches her brother’s funeral. After months of hiding out in the church, Catalina leaves town and joins up with two other army deserters, who eventually die of starvation during their journey. Catalina is rescued by a half-Indian woman who wants Catalina to marry her daughter. At the same time, a local vicar tries to persuade her to marry his niece. Although she accepts their gifts, she eventually abandons them both.

Catalina assists in suppressing the Alonso Ibáñezi uprising and is part of a bloody battle where thousands of Indians are butchered. She is accused of committing a crime that she is innocent of, and although she is tortured, she refuses to admit to it. Soon after, she is accused of a murder that she actually has committed, but she refuses to admit to this crime either. She is nearly put to death until a fellow Basque halts the execution.

In Bolivia, the daughter of a nun begs Catalina to help her escape her husband, who is about to kill her for infidelity. The husband then tries to kill them both, but Catalina gets the woman to the safety of her mother’s convent. Catalina then goes to Peru to investigate crimes in the area. Soon after, she kills a man for insulting her and is sentenced to death. Due to a technicality in the church doctrine, she gains her freedom by taking communion and spitting it into her hand, holding onto the host until she is taken into a church, where she is granted sanctuary.

In Lima, she joins Spanish troops who are being attacked by the Dutch and then returns to the city of Cuzco, where she gets into a bloody fight over a game of cards. She kills her opponent, “the Cid,” who inflicts serious wounds on her as well. Thinking she is going to die, she makes a full confession to a priest.

Although she survives, she is wanted by the law. Her brushes with the constables grow more and more dangerous, and she is eventually surrounded by officers who have been given orders to kill her. A bishop intervenes and takes Catalina into the safety of his house. Catalina finally admits to the bishop that she is a woman, and when he expresses doubts, she gamely offers to submit to a medical examination. During the examination, she is proven to be not only a woman but a virgin, and the bishop vows to help her.

She is sent to a nunnery while the church investigates her past to find out if she ever took vows to become a nun. Her story spreads far and wide, and by 1620 she is well known throughout Spain. When, two years later, it is confirmed that she never took her vows, she is allowed to leave the convent and begin her life as a Spanish celebrity. She goes to Madrid and presents herself to the king, who, in 1625, grants her a pension for her service to Spain.

Catalina travels to Rome, where she meets Pope Urban the Eighth and tells him about her life and travels. She tells him that she is a woman and a virgin, and he gives her permission to continue to dress in men’s clothing.

Catalina ends her memoir with a short tale about being confronted by two prostitutes, whom she insults because they address her as a woman.