Plot
In a meeting with Cardinal Zizka, Brother Diaz learns that he will lead the Chapel of the Holy Expediency, a secretive group within the Church. Zizka introduces him to two representatives of the Chapel, Jakob and Baptiste, who take him to the chapel's hidden dungeon. There, Diaz meets the imprisoned members of the Chapel, referred to by Zizka as "the devils": the necromancer Balthazar, the elf Sunny, and the vampire Baron Rikard.
Alex, a thief, is rescued from a gang by Duke Michael of Nicaea, who identifies her as Princess Alexia Pyrogennetos, the heir to Troy. She is taken to the Church's Celestial Palace, where the Church binds the members of the Chapel of the Holy Expediency to protect her on her journey to Troy, as she is likely to be attacked by her late aunt Eudoxia's sons.
One of the sons, Duke Marcian, ambushes the group with hybrid human-animal soldiers created by his mother. In the fight, Jakob is fatally stabbed while trying to unlock their wagon. Sunny opens the wagon, releasing Vigga, a werewolf and last member of the Chapel. After killing the hybrid soldiers and Marcian, Vigga turns on Alex and Diaz. Jakob, having revived, intervenes and tells her to stop, leading her to transform into human form. Duke Michael, hurt from the battle, parts ways with the group, telling Alex to trust his contact, Lady Severa, upon arrival in Troy.
In an effort to avoid being followed, the group heads to Venice, joining a group of pilgrims. However, Apollonia, the Bishop among the pilgrims, betrays them to get a reward for Alex from Duke Constans. Baron Rikard uses glamour on the bishop and the pilgrims while the group escapes.
In Venice, a group makes a deal with a crime lord named Frigo to gain passage to Troy by retrieving a mysterious box from a cursed house. After retrieving and opening the box, Jakob, Sunny, and Vigga confront terrifying illusions but are saved by Balthazar, who breaks the spell remotely. They deliver the box to Frigo and set sail for Troy, but are attacked by Duke Constans, who rams their ship. As the ship sinks, hybrid soldiers board, and although Jakob is stabbed by Constans, he kills the Duke before the ship goes down.
The shipwrecked group washes up on shore separated. Balthazar, Baptiste, Baron Rikard, and Jakob find themselves in a local war. After they help resolve the fighting, Balthazar tries to perform a ritual to find Alex but instead calls upon a Duke of Hell to free him from his papal binding, although it refuses. Alex and Sunny escape the beach while being chased by Duke Sabbas and his bounty hunters, who are also followed by Vigga and Brother Diaz. Vigga fights off some of the bounty hunters, and the four then take refuge in a ruined abbey.
Duke Sabbas and his hunters arrive, soon joined by Balthazar, Baptiste, Baron Rikard, and Jakob of Thorn. Jakob challenges Sabbas to a duel, allowing Balthazar to raise a horde of undead. The corpses pull Sabbas into a pit. Afterward, the group rests in Sabbas's abandoned camp, where a romance begins between Alex and Sunny.
The group reaches Troy, where Lady Severa welcomes them and leads them to the Pharos of Troy. They prepare for Alex's coronation but are interrupted by Duke Arcadius, Eudoxia's last son, who proposes marriage to Alex instead of fighting. Michael and Severa see the match as essential for politics. Upset, Alex confesses to Sunny that she was not the princess but a common thief who took on Alexia's identity after her death. After Alex is crowned and their mission finishes, the devils plan to leave Troy for the Holy City. In the royal apartments, Arcadius tells Alex he wants a political alliance for Troy's safety, and she agrees. However, her new handmaidens, who were Eudoxia's former apprentices, kill Arcadius. Alex manages to escape and signals for help from the Pharos.
The devils return to help after seeing a signal from their ship. Vigga changes into her wolf form and accidentally kills Baptiste. Balthazar discovers that Lady Severa is Eudoxia, who has transferred her soul to another body. Instead of fighting, she offers an alliance, but Balthazar chooses to stay loyal to the devils. At the Pharos, Baron Rikard kills the handmaidens. Alex tries to escape with Sunny, but Michael stops them and reveals he used Alex to take the throne for himself. Jakob then tackles Michael, and they both fall into the sea.
After the attempted coup, Cardinal Zizka visits Troy to meet Empress Alexia and Brother Diaz, who is now her chaplain. Alex asks the Church to free the devils, but Zizka refuses, stating they are too dangerous. The devils are kept on Zizka's ship until the Church needs them again. Meanwhile, in the Holy City, two people are called by the Church to replace Diaz and Baptiste.
