In the Pilot, we first see Nostradamus talking to Queen Catherine. Nostradamus tells Catherine about his visions with Francis's future is unclear. Catherine states that she wants to control Mary, but doesn't know how. Nostradamus asks Catherine if that having power bothers her. Nostradamus says that Mary is young and pretty. Nostradamus tells Catherine to be patient, that answers will come. Catherine comes upon Nostradamus and asks why the potion didn't work on Mary. Nostradamus states that nothing was wrong with his potion, the delivery of it failed. Meaning that Colin wasn't paying attention to Mary. Nostradamus states that Mary will bring Francis's death. Nostradamus tells Catherine to keep on sacrificing.
In Snakes in the Garden, Nostradamus brings Catherine to the dungeons to show her that Colin wasn't beheaded like they’d thought. Somehow the wrong boy was killed and Colin escaped. By the end of the episode, Nostradamus is washing the ‘X’ off a door there while he speaks to someone. He knows it was she who let Colin free and tricked the jail guards into killing the wrong boy.
In Kissed, Catherine joins Nostradamus in his rooms and he’s making her a concoction to help her sleep. While with Catherine, he has a vision of war which will eventually reach the castle. Henry calls on Nostradamus, asking him to share his wisdom with everyone. He says that a seer in Prague can tell the fortunes of people based on playing cards, and although Nostradamus tries to inform Henry that his power does not work that way, Henry wants him to tell the fortunes of Mary and her ladies. Nostradamus has the girls pull a card and ask a question. He offers general things to Lola and Mary before Henry calls him out on his lack of specifics. Something comes over Nostradamus’ face and then he starts rattling things off to them. To Mary, "The Lion will fight the Dragon on the field of poppies." To Greer, "You will fall in love with the man with the white mark on his face." To Aylee, "You’ll never go home." Mary goes after Nostradamus, asking why he would scare her friends. Mary knows Catherine was not behind it, so she asks who he serves. He says he only serves the realm, himself and the truth.
When Sebastian is wounded, he is brought to Nostradamus, who sees his vision again and understands that the war was brought into the castle through the attack on the French troops and Sebastian.
In A Chill in the Air, Nostradamus is working to save the carriage driver’s life while scolding Bash for interrupting a blood sacrifice which will put Bash in danger. Nostradamus warns Bash to stay close to the castle, or he’ll be in grave danger.
In Fated, he discusses with Catherine about the prophecy of Francis. He claims he the prophecy hasn't changed and the Francis will die if he is wed to Mary. Later Nostradamus sees another prophecy of death in the castle and he tells Mary of what he saw. Mary shares with her ladies-in-waiting that he said one of them would die before the first frost falls. When the death occurs, it is Aylee. She claims Nostradamus was right and she will never be going home. Mary then calls Nostradamus the devil. Nostradamus knows that Cathrine couldn't have possibly done this, so he leads the trail straight to Clarissa. As Nostradamus chastises her for what she has done, he removes her bag of her head and makes her look Aylee in the face. Clarissa is forced to look Aylee in the eyes.
In For King and Country, Nostradamus takes a doll into the castle passageway and gives it to Clarissa, who he has locked in a cage due to her culpability in Aylee's death. He notes that she feels no remorse for what she did to the young girl and reminds her that while kings and queens might be allowed to play God, people like her are not. She was given all the freedom she could have wanted if she just stayed out of sight and didn't harm anyone, but now, he threatens to starve her if she continues to misbehave.
In Inquisition, Catherine pays a visit to Nostradamus in the dungeon and brings him water before asking whether Bash had ever seemed too in the know about the pagans in the blood woods. Nostradamus admits that Bash's hunting in the woods could lead to him seeing things and as Catherine apologizes to him for getting him caught up in this, Henry comes into the dungeon to offer a deal. If Nostradamus testifies that the affair actually happened, he would simply be exiled from France rather than executed, but Nostradamus remains loyal to Catherine and rejects the chance to save his own life. Also Nostradamus past about Clarissa is revealed.
In Royal Blood, Nostradamus brings a Bible to Catherine in hopes of providing her absolution before her scheduled execution. However, she rejects his advances and suggests that he bring her poison, as she doesn't want Henry to have satisfaction about the spectacle surrounding her beheading. Later, Nostradamus and Catherine's guard bust into her room and find that she's hung herself from the ceiling with a rope that had been left. They get her down and Nostradamus pledges to bring her to the infirmary, only to take her to her chambers and revive her. Catherine's ready to make her escape to Italy so that she can regain her strength but her journey gets derailed when Nostradamus informs her of the children being kidnapped. He tells her of Bash sending men to find the boys and she thinks that Bash was the one responsible for the kidnapping in the first place; Catherine promises not to leave the country until she knows the boys are safe.
Due to Catherine's firstborn, Clarissa's death, Nostradamus' sees a new vision which is of Mary and Francis in Consummation. Francis and Mary are happy while being married a year and they have children. He tells Catherine about the change in his visions and she goes through quite the range of emotions before settling on anger when he suggests her life might be saved now since she’ll no longer oppose Francis and Mary’s union. It’s gone past her standing in the way; she’s been found guilty of adultery and is going to be beheaded. She tells Nostradamus that if she can’t turn things around she’s going to make sure he burns before she’s executed.
However, Clarissa is revealed to still be alive and Nostradamus’ vision changes again by the end of the episode to include Francis’ historically accurate death of an ear-related disease, but he does not tell Catherine who is in a wonderful mood due both to her son’s happy union and her own pardoning.
In The Darkness, Nostradamus continues caring for Olivia, who has miraculously recovered from the state she was in when she arrived at the castle. She informs the prophet of what she knows about where she went; after she got lost in the tunnels, she ran out into the woods and into a group of peasants who kidnapped her and brought her to the Darkness, a creature who lives in a dark, cold cavern. It fed on her for nights that turned into weeks and eventually months, the only way she survived being the weight she lost from barely eating and drinking. That allowed her to slip out of her chains and back into the forest, where she found a stream and eventually Bash. Later, Nostradamus wakes Olivia up with food and new clothes; he says that it's time for her to join the ranks of the living, even though she wants nothing more to do with French court. She wants to stay there with him and live out the rest of her days away from other people, as she believes that the Darkness knew that she was a bad person and filled her with evil during her time in its lair. Nostradamus takes Olivia to a nearby pond and baptizes her, telling her that evil is a choice and that all that matters is what she chooses to be. He encourages her to hang on to who she thinks she is, for it will be her salvation, and she claims that she feels anew.
In Monsters, Nostradamus comforts Olivia from a nightmare, assureing her that the Darkness can no longer reach her. Nostradamus notices an infected wound on her back, he drains it and finds a tooth from the Darkness embedded in it. He shows it to Bash, Francis, and Mary, telling them that the Darkness is, indeed, human, that the tooth embedded in Olivia's back was filed to look like a fang. Bash and Francis head out to hunt down the Darkness.
Nostradamus gets Olivia back into society. She attempts to get Nostradamus to dance with her but to no avail. Outside, Nostradamus admits to Olivia that the last time he danced with a woman was with his deceased wife, who died along with their young children in the plague. As a result, he dedicated his life to saving others; Olivia then tells him that he saved her before kissing him.
In No Exit, Nostradamus plans to leave the French Court and start a new life with Olivia. However, Catherine interferes with his plans, by trying to kill Olivia. He feels the only way to protect Olivia from Catherine is to send her away to Trinidad without him. He tells her of a false vision, saying that it was of her happy with someone else, and warns her that if he went with her, Catherine has to reach to take them out. He informs her that his cousins will look after her, the two part with a final kiss.
In Long Live The King, Nostradamus looks after a child that Bash brought back with him from the Blood Wood. Nostradamus says the blood he is covered in did not come from him, since there are no cuts or bite marks on his body. Bash and Nostradamus start interrogating him about the whistle, but Kenna stops them. She asks the boy if he is alright, informing him that no one will hurt him at the castle. Nostradamus thinks the boy will open up to someone with a softer touch, indicating Kenna. Pascal says that the man with the sharp teeth took him to a place in the mountains. Bash tells Nostradamus that the name of the place is a pagan word, meaning where darkness rises. He admits to being born a pagan and wanting to redeem himself for sacrificing the two lives that he did in the Blood Wood. Nostradamus wants to go with him, since the Darkness touched Olivia as well.
In Slaughter of Innocence, Nostradamus and Bash are on horseback, riding through the trees and coming upon a small town in the distance. Bash and Nostradamus finds the town that Pascal told them about. The place is deserted, but they find a room where a body was recently sacrificed. On the walls are predictions of natural disasters that have happened in the past:fires, floods, and such. The most recent was the eclipse that Bash saw when he found Pascal. The only one left was one with stars falling from the sky. Underneath the picture, there is a rhyme that Pascal was saying, but the last line was blocked by dirt. Bash reads it to Nostradamus, and the last line is “I am Darkness”. Nostradamus and Bash arrive to rescue Kenna and Pascal. While Bash fights the Darkness, Nostradamus helps by stabbing the Darkness in the back. Once Kenna and Pascal leave, the Darkness tells them that he was sacrificing to the gods to prevent the plague from returning to France. Nostradamus tells Bash that he has had visions, but Bash sends him along with Kenna and Pascal.
Back at the castle, word has come from nearby villages saying that the Plague has begun again and is spreading fast. No one is allowed to leave or enter the castle.