A two-year old European girl grows up in an Abbey. Her name is Radegunde. At a young age, she flips through a book and her Abbess believes her to just be pretending to read. However, Radegunde explains the context of the book, which surprises and frightens her superior. This is all explained by a young errand boy, who then talks about how Radegunde becomes the next Abbess. Abbess Radegunde is known to be very kind to people and knew all the languages of the world. She was an impatient individual, but not one that got angry. The people in town believed her to be a saint.

One day, boats arrive on their shore and the errand boy runs to the Abbey tower to warn others. People become very afraid and Abbess Radegunde explains that God will protect their souls. She tells a priest--Father Cairbre--to take the younger sisters to a safe place and then tells another sister to keep the villagers safe.

The ships turn out to be those of Norsemen. Abbess Radegunde goes to greet the intruders and the errand boy notices she pulls out her crucifix. The errand boy thinks God will send his lightening down to kill the intruders, but nothing happens. Instead, the Abbess goes and meets the Norsemen and speaks in their language---which surprises them.

The person who seems to be the leader is named Thorvald Einarsson and finds it strange that she knows his name. Abbess Radegunde sits down and talks about how she learned the language from his friend and proceeds to prove that she knows his friend. Thorvald Einarsson claims that he is not the leader and that the men he brings with him are not under his control. The Abbess begins walking around to see the different men and one of them pulls her headdress off. However, she is not ashamed and proceeds to intimidate the young man until he becomes embarrassed and cries. The boy's name is Thorfinn and she feels somewhat bad for making him upset.

The Abbess asks the group about who is willing to make a bargain with her and then tells a riddle. They tell her that they want to raid the monastery, but she explains that half of the treasures are in her head and that if they try to kill her, she will not tell them the treasures. Thorvald then agrees to bargain with her. The only reason the errand boy understands what is going on is because Father Cairbre can translate it. The Abbess asks for the errand boy to join her and he does. The errand boy notices differences in the Norsemen's clothes and how they smell strange. Father Cairbre also comes so he can translate the bargain back to the other priests.

Thorvald asks Abbess Radegunde if they are poor and she explains that they are rich, not only because of the gold but because of their knowledge and their faith. Thorvold says he prefers the gold and riches, but she convinces him that her people are the most important treasure. She tells her people that if the Norsemen fight them, they should destroy everything so they receive no riches.

Thorvald explains that his men have not had women in a long time and she makes a joke that amuses the Norsemen. Thorvold agrees to enter the gates with five men to search for the riches and Radegunde agrees to go with him. Thorfinn tries to take a crucifix from one of the younger sisters--Sister Sibihd--but she initially refuses until the Abbess convinces her to give it to Thorfinn.

However, the errand boy is suddenly pushed down by Abbess Radegunde, who protects him as the Norsemen slaughter the people that were around him. Thorvald explains that he protected her and the errand boy and she should be thankful for his kindness. The Abbess thanks him. The errand boy asks the Abbess to go see his stepmother and father, but the Abbess stops him because his parents are dead.

Amidst Norse control of the village, Abbess Radegunde asks the errand boy if he would like to go to Constantinople with her because that is where Thorvald wants to sell her. Then, Thorvald asks Radegunde if she can sit by the sick and heal them. Thorvald takes her to Thorfinn who is nearly dying. Thorvald's men try to stop her from approaching but she convinces them that she must help Thorfinn. Thorfinn wakes up and says that he has beat her because he was able to get treasure, fight, and sexually assaulted Sibihd. Radegunde explains that Sibihid was not an intelligent nun and Thorfinn should've had sex with the more intelligent woman. In his final minutes, she comforts Thorfinn and tells him a story about women. Thorfinn asks her to pray and she tries. Thorvald runs to her later and says that Thorfinn has been healed. Thorvald also asks Radegunde to stay awake to talk, but she insists that she sleep because she is tired. Thorvald further asks to be baptized but she explains that she won't until he is a different man.

Abbess Radegunde takes a bath and then helps heal the other sisters. She then tells Sister Hedwic a story to make her feel better about not having sex. She explains that once she was attracted to a statue of Apollo and dreamed about him pleasuring her. However, a young man once pursued her and forced sex onto her and it was not as she imagined. This sent Sister Hedwic into fear and she then felt less bad about her situation. Sister Sibihid begins to cry because she is bleeding from the assault and is traumatized from the overall attack, and Radegunde comforts her. Thorvald asks her if he is a bad man and she explains that he is not, he just has a bad group of men. He hits her and she explains that the women all want to be a mother and that there are too many fathers in his country. He thinks her to be a witch and she denies it. She says that he is clever and that she wants to be his friend.

Then Thorvald asks the errand boy if he wants to see his country, but that he has to be his slave. The errand boy retorts, saying that he would rather fight. The Norsemen and the priests sleep on pallets in the study, resting before their day of travel the following day.

However, Abbess Radegunde awakens and begins shouting that she sees her people. Thorvald and the others think that she has been possessed and try to get her to stop. The people think that she a demon. The boy thinks that Radegunde's body is being possessed. The demonic Radegunde tells Thorvald to move in different directions and that there is another demon inside of him, controlling him. He tries to resist this possession, but she controls him still. The boy feels bad that Thorvald is getting punished and asks the demon of Radegunde if the bad version of Thorvald will get free. Then the demon tells the errand boy that she cares for him and he falls asleep.

For the next three days, people bow down to the demon. They weep to the demon and the demon tells them to follow her into the woods. However, as they walk, the Norsemen start to disappear one by one. The boy sees bright light and men and women in that light. The demon runs to them and weeps. They embrace it. Then the demon goes to Thorvald and explains that Radegunde is no more. Her revenge is making Thorvald into someone who hates war. She makes him leave and then tells them that she will be leaving as well. She tells the errand boy to remember her and be content.

Three days after the Norsemen leave, Sibihd recovers from the trauma of the attack, and Thorvald becomes a monk for the rest of his days. The priests talk about the demonic Abbess Radegunde often and the errand boy believes that she wasn't a saint.