Through the Moon is the first graphic novel of The Dragon Prince. The story is set between the events of Book Three and Book Four and is considered canon. It is available for purchase through Amazon as Kindle, paperback or hardcover.

The Dragon Prince has been reunited with his mother, the Human Kingdoms and Xadia are at peace, and humans and elves alike are ready to move on.

Only Rayla is still restless. Unable to believe Lord Viren is truly dead, and haunted by questions about the fate of her parents and Runaan, she remains trapped between hope and fear. When an ancient ritual calls her, Callum, and Ezran to the Moon Nexus, she learns the lake is a portal to a world between life and death. Rayla seizes the opportunity for closure-and the chance to confirm that Lord Viren is gone for good.

But the portal is unstable, and the ancient Moonshadow Elves who destroyed it never intended for it to be reopened. Will Rayla's quest to uncover the secrets of the dead put her living friends in mortal danger?

Caught inside a merciless nightmare, Rayla returns to the dragon lair inside the Storm Spire; the same place where her parents had faced Viren on the day Avizandum had been slain. Three pillars of ice tower in front of her, which she examines one by one, discovering in shock that two of them contain Runaan and her parents. To Rayla's surprise, Viren shows up behind her and showcases the new addition of his collection: the third pillar containing Callum. Although Rayla commands the mage to step away from her boyfriend, Viren reassures her that she would be joining them soon enough. As the two ready for battle, a large feather descends onto the scene.

Rayla wakes in a bed inside the kingdom of Katolis, as Callum uses the feather to tickle her face, leaving her disgruntled. Callum admits that he hoped for his girlfriend to make a cute face, but neither Rayla nor Ezran are supportive of him using Phoe-Phoe's feather for such a silly action. Before Callum is able to defend himself, Ezran informs Rayla that a letter from Lujanne has arrived, which instructs that the "ghost feather" has to be returned to the Moon Nexus before the next new moon, in order for a ritual of rebirth to succeed. Seeing as the next new moon is only three days away, Rayla wishes to depart as soon as possible, when she realizes that everyone had gotten up hours before her. Due to being the new king of Katolis, Rayla inquires if Ezran would be able to join them, but he promises that a note left for Opeli would excuse him for such an important mission. Opeli is briefly shown in her office, anything but fond of the development, before Ezran storms out to pack.

Since they are now alone, Callum asks if Rayla had stayed up late again, to which she replies that she could not stop herself from worrying over Viren's fate, as they had not found a sign of his body after he had dropped from the pinnacle of the Storm Spire. Despite Callum's attempt to soothe Rayla's mind by saying that Viren is dead for sure, Rayla refuses to move on without proof. Callum's emphasis on the topic of moving on sparks Rayla's hurt about having lost both her parents and Runaan without closure. Once Callum admits that he hates seeing Rayla in this state, she manages to calm down and leans against him, which gives him the opportunity to suggest that they should treat the trip to the Moon Nexus as a vacation, one that Rayla gratefully confirms she needs.

Team Zym eventually arrives at the Cursed Caldera, accompanied by Soren. Just as the two princes converse about the level of creepiness surrounding them, Lujanne's illusion spider jumps out at the group and screeches into their faces. Hardly fazed, Rayla recalls them speaking about the illusions before and how they are not of solid nature, which leads her to freak out once her hand actually touches a solid surface upon meeting with the spider's face. While most of the group tries to stomach the experience, Lujanne reveals herself to everyone, mighty proud of her successful prank. Once Callum asks her how she managed to make her illusion appear solid, Lujanne credits the development to her companion Allen, who gives the group a friendly greeting. Rayla and Callum quickly recognize the man as the challenger that had faced Tristan in the village they had visited, before he had stormed off in tears. Lujanne teases him, though Allen thinks that there is no shame in crying. When she continues to explain that the illusion gained a solid form through a spider-like wood construction Allen had built, he nicknames her "Janey-Lu" and Callum asks if the two are a thing, to which Lujanne winks in response.

Ezran finally approaches Lujanne and hands over Phoe-Phoe's feather, letting Lujanne know that she had sacrificed herself for him. Lujanne expresses her aching pain of missing her loyal friend during this phase of rebirth and explains that Moon Phoenixes are tied to both life and death and that, when the time comes, she would place the feather on the water of the Moon Nexus's lake. Until this time comes, she asks for Ezran to hold on to the feather. Out of hospitality, Lujanne then invites the group to eat, but they insist they brought their own food, not wanting to be fed grubs again.

At the table, Lujanne inquires how Callum and Rayla fell for each other. Although Callum wants to recollect their starting point by mentioning their first kiss in the Midnight Desert, Rayla begs him not to bring this moment up. Lujanne notices that things between humans and elves are beginning to change, when she is asked how her own relationship with Allen came to be. She explains that she had only meant to mess with some humans while in her disguise, when she met Allen and went on a date with him. When her missing fingers were noticed, she describes "a lot of pitchforks" to have been involved and Rayla reminds her that she has to wear gloves. When Lujanne expresses her gratitude that they had managed to make a difference thanks to Phoe-Phoe's sacrifice, Rayla voices her concerns about Viren having simply vanished without a trace, but is interrupted immediately by Callum. He excitedly informs Lujanne that he knows the Sky Arcanum now. When Lujanne reminds him kindly that they have been over this, not taking him serious, Callum blows a gust of air over the table by casting "Aspiro", causing Phoe-Phoe's feather to be blown away. Ezran tries his best to stop Bait from eating the feather, while Rayla's expression fills with worry.

Later, at the lake, Lujanne signals that it is time to place the feather on the water and explains that life and death are an endless cycle, which is embodied by the moon. The group is asked to hold hands and Lujanne continues to preach that death is not an ending, which causes Rayla to grow sad. She then highlights how Moon Phoenixes, while connected to both life and death, are part of this cycle and thanks the old Phoe-Phoe for what she has done to make room for her new self. The feather then touches the water and transforms into an egg, which is picked up by Lujanne. Callum jokes about having to go on a quest to hatch this egg as well, when it suddenly cracks. Lujanne cracks the egg open into Ezran's hands and a new Moon Phoenix hatchling falls into his palms. The group welcomes Phoe-Phoe back, then leaves the lake. Rayla suddenly jumps off into a bush, which goes unnoticed by everyone but Callum.

Rayla sneaks off to a secluded rock at the lake to think, when Callum stumbles out of a bush and asks her what she is up to. Although she sarcastically implies that she had wanted to be alone, she invites her boyfriend to sit with her and admits that the death ceremony had done little to distract her. She finds it unfair that only Moon Phoenixes can be reborn, though Callum is grateful for this phenomenon to not apply to Viren. However, Rayla was hinting at the fate of her parents, who could not simply be reborn inside a silver egg, and wonders why the portal between life and death can not be reopened by Lujanne, allowing her to check if her parents had actually died. When Callum tries to express his sympathy by beginning to say that he knows how she must feel, Rayla lashes out, doubting that he does, considering he had wanted her to move on. Callum defends himself by saying that she is not the only person who has lost people she loved, and when Rayla cries out that he at least knows what happened to them, Callum reminds her in tears that one of the people she worries about had killed his stepfather Harrow. Rayla comes to the conclusion that neither them, nor the world has moved on and storms off, leaving Callum alone, wishing she had not left.

The following day, Rayla enters another nightmare, in which she witnesses Callum getting shattered by Viren. She bolts awake in tears, screaming out his name, but realizes he is still asleep. When Callum wakes up a bit later, he notices that she has left on her own and wonders if he screwed up. Seeking advice, he finds Lujanne, who tells him that lies are part of a relationship and that white lies are illusions built to protect the hearts of the ones you love. She gifts him two Moon Opals and believes in the Moon Arcanum and the change it brings. Callum suddenly realizes that the only spell that could help Rayla now would be the portal of life and death, but Lujanne warns him that entering this portal could end in him being pulled to souls of the dead he had a connection to, whether they were made of love or hate. Lujanne reassures him that it is not possible to go through with the ritual without the Moonhenge either way and refuses to repair its ruins, despite Callum suggesting to do so.

Meanwhile, Soren and Allen are sparring while Ezran and Bait watch them. Rayla itches to join the play fight and jumps in without a warning, but is tripped by Soren and falls into a mud puddle. When Soren asks if she wants to join their training sessions, Rayla admits that she wants to talk instead and borrows him for a while.

After leaving Lujanne's meditation place, Callum stands at the Moonhenge and crushes his Moon Opal to cast "Historia Viventem", which reveals the spell "Mors Aperta" to him through an image of the past.

Soren and Rayla find a secluded place in the forest, where Rayla asks him what had happened to the band of Moonshadow Elf Assassins that had entered the castle after her. Soren informs her that they have all been killed and turned into a magic spell, with exception of Runaan. Though he can not say for sure, he suspects that Viren has killed him as well. Soren suddenly begins to regret not having killed his father at the Storm Spire, as he shares Rayla's worry about not having found a body, considering how easily his father fools others.

At evening, Rayla reunites with Callum in their bedroom, where Rayla tells him what she has been up to, then asks him if he is studying magic. He tells her about the potential of restoring the portal and Rayla seems willing to risk the danger for her closure, until swimming in water is mentioned. When Callum pulls the idea back, Rayla insists that they do it, as she needs to know Viren to be dead for good. The two decide to lie to Lujanne about restoring the Moonhenge and Callum lets his girlfriend know that he is ready to jump into any danger for her, before the two nuzzle affectionately. Callum hopes she finds closure for her parents, then asks if Rayla thinks them and Allen have become friends now.

Callum and Rayla approach Allen to ask him to help with construction a "surprise" for Lujanne. They justify the reconstruction of the Moonhenge by pretending that they want to build something new from the hands of humans and elves from the ruins, effectively convincing him to help out. As they do not have enough workers to reconstruct the entire Moonhenge, they settle for building a frame instead. Allen worries how they can hide this project from Lujanne, but is confident they can get the work done before she is done meditating. When she walks in on them later during the day, they describe the wood to be illusion practice for Callum. Everyone works hard into the night and Allen proudly suggests to take a breather and show Lujanne their surprise in the morning. However, Rayla and Callum stay behind under the pretense of needing to rest, then begin to reenact the ritual. Callum performs a couple of dance steps, when the construction begins to break. He manages to cast the spell just in time before their construction collapses and the portal opens inside the nexus, which alarms Lujanne, who rushes to warn the two. Before she can reach them, Rayla escapes and manages to jump into the nexus. Just moments after she had jumped in, her lifeless body swims up to the surface and Lujanne asks Callum what he has done.

On the other side of the portal, Rayla crawls to the shore, then begins to wander around. She quickly realizes that the night of Harrow's assassination is being replayed, when four shadow elves with readied weapons appear behind her.

Back in reality, Callum makes sure Rayla is okay. Although Lujanne says she is fine for now, she warns him again of how dangerous this portal can be and advises him not to try and pull her out of the water, as she would become an empty husk with her soul trapped on the other side. She hopes for Rayla to return before sunrise, as her soul would be lost forever if she returned any later.

Meanwhile, Rayla flees and dodges the attacks of the shadow elves, who mock her for being an assassin that refuses to kill. After they repeatedly attack Rayla and accuse her of having failed them, they notice her missing binding and conclude that she has carried out her mission after all, despite Rayla's attempts to correct them, allowing her to proceed. After entering a cave, she stumbles upon a large cocoon, which contains a sleeping Viren inside. When she holds out her blade towards the cocoon, the souls of fallen soldiers emerge from behind her and pull her in, just when Viren suddenly opens his eyes and directly looks at her.

On the other side, her body threatens to drown and Callum rushes to save her, but is stopped by Lujanne, as he would be stuck between life and death. Ezran has the idea to borrow a feather from Phoe-Phoe, which allows Callum to stay tethered to the world of the living, as he dives into the nexus to save Rayla. He manages to reach her hand, but is attacked by a soldier, causing him to lose the feather. As both of them are now trapped, the two are surrounded by enemies. In order to reach the feather floating nearby, Callum casts "Fulminis" to force the soldiers back, then boosts Rayla into the air using "Aspiro". When she reaches the feather, she returns to Callum and the two swim back up to the surface, where Rayla reinforces her hatred for water. The two embrace and kiss, while the rest of the group watches them in relief.

At dawn, the couple sits on a rock when Rayla sighs. When asked how she is doing, Rayla forces herself to accept that her family is gone and that she will find no closure. Although Callum tries to lighten the mood by suggesting a real vacation, Rayla confesses that she saw Viren webbed into an odd cocoon. Callum believes this to mean that he is dead, but Rayla firmly believes that he is alive. Not wanting her to go alone, Callum insists they search for him together and Rayla promises him they would, before the two confess their love for each other once more. At night, Rayla dresses in her cloak and recites Lujanne's words about white lies, leaving a single kiss on Callum's head together with a letter, before she departs into the dark forest and the approaching storm on her own.