An unusual circus named Le Cirque de Rêves shows up in a city. There are no bright or joyful colors; it is a black, silver, and white scheme, and it is only open at night. The magic atmosphere of the place fascinates everyone who enters the gates. One can hardly argue with the fact that it seems to be genuinely enchanted.
Two magicians, Prospero the Enchanter (whose real name is Hector Bowen) and a man named Alexander (who is known by others as simply A.H.), are sworn rivals. Endeavoring to find out who is stronger, both men choose a student, teach them, and start them in a competition. Every spell they perform is noted; to end the game, one must exhaust their opponent to death. After losing the last game, Hector is determined to win this one. He is confident that his choice of his daughter Celia is a wise one, for she is naturally skilled at illusion. Unfortunately for Celia, her father is a rather strict, even merciless, teacher.
A.H. works in an entirely different way. After finding an appropriate candidate, a little orphan named Marco, he instructs the boy to study on his own. Thousands of books are his only company, and Marco rarely ever interacts with A.H. A bright spot in his life is when he meets Isobel, a tarot reader. She is impressed with his magic and the two begin a relationship.
The venue for the game becomes clear at a dinner party held by Chandresh, a wealthy eccentric, and attended by the Burgess sisters, Mme. Padva, and Ethan Barris, an engineer and architect. Chandresh excitedly tells them of his plans to open a stylish and fantastic circus that is only open at night and features the most wondrous attractions, and they are all very interested in helping out. By the time of this meeting, Marco is also working as Chandresh’s assistant. Chandresh knows nothing of the boy’s knowledge of magic or the game itself.
Preparations for the circus begin in earnest. Chandresh and his companions begin to hire talent, beginning with the enigmatic contortionist Tsukiko. When Celia comes to an illusionist casting, Marco immediately realizes that she is his opponent, but he says nothing to her. Since he is not allowed to leave London often, Isobel decides to apply to be a fortune teller at the circus so she can provide any insights to Marco about Celia.
The circus finally opens. A magical bonfire springs up and continuously runs; a pair of twins are born that night. They are nicknamed Poppet and Widget, and they have the run of the circus as they grow up. Poppet can see parts of the future, and Widget can read people’s pasts on them.
The opening initiates the years of competition. Marco and Celia do not know the rules of the game, but they design the most fantastic elements of the circus, such as the Ice Garden, the Wishing Tree, and the bonfire at the gates. Finally, Celia realizes who her opponent is, though his presence in the tents was always palpable to her.
Although the pair do not see each other often because the circus constantly travels and Marco stays in London, they feel that they share a strong connection, which turns into true love. They agonize over what the game entails and how to make sure that no one is hurt, for by this time it is clear that all those who created and work for the circus are indelibly caught up in the web of magical rivalry.
Tsukiko reveals herself to Celia as the winner of the last game and tells Celia that to end the game one must die; however, the other problem is that either Celia or Marco’s death is going to be the death of the circus, too.
This pains Celia to hear because, over the years, the circus has indelibly impacted thousands of people’s lives. A group of admirers started by the circus’s famed clockmaker, Herr Thiessen, calls themselves the rêveurs and follows the circus around the world, writing of their remarkable, often life-changing experiences.
Another person entranced by the circus is Bailey, who, as a child, took a dare to enter the circus during the daytime. Amid its disconcerting silence and stillness, he met Poppet (though he did not know her name at the time). He could not forget her red hair and how she gave him a white glove and showed him how to get out of the labyrinthine tents. Bailey visited the circus as often as he could as he grew up. He finally met Poppet and Widget and began to go every night to spend time with them, immersing himself in the circus.
Poppet and Widget have long been aware that the circus has been changing for the worse. They see cracks and stress, though they do not know what is happening. Poppet knows Bailey has some role to play if the circus is to prevail (though the particulars are unclear) and comes to him to ask if he will join them forever. He says he needs to think about it, but after Poppet leaves, he realizes that he will certainly go with them. Unfortunately, when he shows up at the appointed time, he sees that the circus has packed up and left early. He joins a handful of rêveurs to travel to the circus’s next location, hoping he is not too late to help with whatever Poppet and Widget need him for.
Marco learns that Celia is going to try to sacrifice herself, so he attempts to destroy himself first by jumping into the bonfire. As soon as Celia sees this, she joins him and flames encircle them. She manages to perform a spell which rids them of their physical bodies and lets them stay alive incorporeally.
The pair are finally free and together. Bailey arrives and performs the rituals to take over the circus as its new caretaker, and the circus is able to endure.
