The cover depicts the titular character, Vanitas, perched on the inside edge of a gilded frame, crafted in the shape of skulls and floral designs. In his hand he holds the Book of Vanitas, and in the frame behind him is a blue moon, hanging in a sky filled with constellations.
Rumors revolving around The Book of Vanitas, a clockwork grimoire of dubious reputation, draw Noé, a young vampire in search of a friend's salvation, to Paris. What awaits him in the City of Flowers, however, is not long hours treading the pavement or rifling through dusty bookshops in search of the tome. Instead, his quarry comes to him...in the arms of a man claiming to be a vampire doctor! Thrust into a conflict that threatens the peace between humans and vampires, will Noé cast in his lot with the curious and slightly unbalanced Vanitas and his quest to save vampirekind?
A young Noé is shown with his master, who tells him that he mustn't ever let his true name be stolen by anyone, as it forms the constitutive equation of his existence. In other words, his true name is his very life.
A bulletin is broadcast, detailing how Vampires have appeared in Paris and are draining their victims of all their blood - raising the question of whether or not the Vampires are out for revenge against the humans. Thus far nine victims have been found with bite marks on their neck and rumors begin to spread that The Chasseur are only now moving in on the churches.
As a crowd of people voice their fear about the current situation with the Vampires, the voice of a woman cuts through - saying that she's very cold.
Aboard the airship, La Baleine, citizens continue to clamor about the threat of the Vampires. One woman asks if her notion that the Vampires were annihilated long ago when they lost the war against the humans. Another asks if some then survived somehow, admitting that the notion frightens her. Even so, a man insists that Vampires are nothing more than a fairy-tale, while another claims that his great-grandfather had allegedly seen one once. The first man argues that his companion is just spouting another one of his horror stories, prompting the second man to suggest that even if that were the case, they'll have nothing to worry about if the rumors about The Chasseur moving in on the churches is in fact true. As Noé listens to the gossip from afar, he notices a young woman wrapped in a shawl waver, as she appears to be unwell. As she falls, Noé rushes to her side and catches her in his arms, asking her if she's alright.
In a flashback, while Mina plays in the distance, Noé sits and reads quietly alongside The Colleague; who asks him if he knows about the "curse-bearers". He goes on to tell Noé that his grandfather had once told him that a curse-bearer is a Vampire who becomes strange or violent out of the blue. Noé questions whose curse it is, prompting an angered response from The Colleague - who states that the answer is obvious as he slams his hand down into the tree they're leaning on and proclaims that Vanitas is to blame. As The Colleague's hand begins to bleed, Noé asks if he's okay - only to have The Colleague lick the blood from his wound calmly and ask if whether or not Noé would still see the Blue Moon as beautiful if he had one of the curse-bearers standing right in front of him.
Noé is shown writing a letter to his teacher - explaining how he'd departed for Paris shortly after receiving his letter - only to get himself involved in an incident while aboard The Baleine that coincidentally lead him to meeting Vanitas; a regular human who claims to have inherited The Book of Vanitas from Vanitas of the Blue Moon and identifies himself as a Vampire medical specialist. Additionally, Noé adds how Vanitas had saved a Vampire right before his very eyes. Noé is then shown telling Vanitas that there's something that he'd like to ask him. Vanitas encourages Noé to come out with it, and so Noé asks why they're in prison - which Vanitas admits is a good question.
As Noé storms out of Galerie Valentine, Vanitas asks him to wait a second and whether or not he even knows where he's going. Noé admits that he has no idea, which Vanitas had initially assumed and proceeds to grab Noé by the shoulder and tell him to calm down while they figure things out; much to Noé's discontent. Before he make much of a fuss however, a bat flies into Noé's face, though Noé only gets to examine it for a short while before it turns away and flies back to its master, Dante - who remarks that Vanitas looks to be having some difficulty. Vanitas is stunned to see Dante again, while Noé passively remarks that Dante was the one who'd helped Vanitas break into La Baleine, while running over to Dante Vanitas accuses him of simply leaving Amelia and running off to save himself, to which Dante explains that it wasn't his job to protect the target; mentioning that he does more work than he's paid for as it is. After a quick trade of insults, Vanitas notices that Noé seems rather confused and out of place, deciding that he'd better introduce Noé to Dante, adding that Dante is an information broker he uses frequently - only to correct himself by calling Dante a "jack-of-all-trades" who is willing to do pretty much anything so long as you pay him. Dante voices his surprise that Vanitas is working with Noé, prompting Noé to remember that Vanitas had called Dante "baldy" on La Baleine - frustrating Dante, who'd rather not be remembered like that, as he's not even bald.
A proud Vanitas mentions that while he doesn't know why Dante's there, Dante's out of luck, as he's been replaced as a shield by Noé - which Noé immediately denies - only for Dante to voice his shock before adding that he'd never been Vanitas' shield. Vanitas continues, saying that Noé is much stronger and sturdier than Dante and doesn't cost him any money - making Noé the perfect partner - again, something which Noé denies. Telling Dante that it's simply the way things are, Vanitas brushes Dante off and returns to Noé's side; claiming that if Dante wants to earn pocket money he'll have to do it somewhere else. Amused, Dante says that it's too bad things have to be that way, as he'd figured out how to find the "nine-fold murderer" and had sought out Vanitas in order to tell him. Immediately, Vanitas drops to the ground and praises Dante at his feet, calling him splendid and incredible all while saying he knew that Dante could do it.
Johann and Dante race across the rooftops of Paris - with Johann expressing his outrage that Dante would send Riche out after a Curse-Bearer all alone and asking what Dante could've possibly been thinking. Dante voices that the blame doesn't rest only on him, as Riche said that she wanted to help and so he simply allowed her to do so. Johann states that Riche was obviously just worried about Dante because of all of his recent idiotic stunts, mentioning that he hopes Riche is okay. Hearing this, Dante tells Johann that he's over protective and suggests that he instead allow Riche to take care of herself - only for Johann to quickly tell Dante to shut up and explain that this is why he can't stand brutes who can't understand a girl's feelings.
Luca is shown leaning against a wall - remembering how Jeanne had told him to find some place safe to hide. Determining that he can't just hide while Jeanne fights for him alone, Luca takes off in search of Jeanne in order to help her.
Meanwhile, Jeanne chases Noé throughout the streets of buildings - jumping from building to building while Noé runs through the streets below. As Jeanne dives down and attempts to strike Noé with Carpe Diem, she demands to know where Vanitas disappeared to, only just missing Noé as he moves out of the way in time. At this moment, Vanitas jumps through a nearby window in an attempt to drop kick Jeanne - though she simply grabs him by the ankle and throws him at a nearby wall - though fortunately Noé catches him before he can make contact. Vanitas commends Noé's abilities and asks if he can throw Noé in return - which Noé outright denies just as Vanitas slashes a pile of crates that fall onto Jeanne while Noé swings away on a nearby bridge. Noé admits that Jeanne is amazing, as her reactions are so quick that he can't get close enough to deal with her Crimson Gauntlet - which Vanitas agrees with, though he mentions that Jeanne is a lot more tame than he'd thought - and while this confuses Noé, Vanitas mentions that it is beside the point and that the plan is to go as he'd told Noé earlier.