Renowned novelist and owner of the Fantastic Kamiyama Bookstore, Touma Kamiyama wakes up after witnessing the same dream, where Wonder World invades the Real World! There in the midst of a war between several Kamen Riders, Touma is unable to save a little girl who pleads for help, until she was suddenly saved by a swordsman! A Wonder Ride Book was left in Touma's hands as he wonders "Why do I have this?" "I think I'm forgetting something important... Something I must do." Touma takes his editor in charge of his latest manuscript, Mei, to present a copy of his book to Ryota when in town for their birthday. Just then, the color of the sky suddenly changes, as strange things start to happen! The world as Touma knows it is about to change right before his very eyes...!

Entrusted with the powers of the Sword of Flames, Touma Kamiyama has saved the city from a dreadful incident! But the mysteries surrounding the sword, the books, and this strange new world only deepened! Soon, Rintaro Shindo appears before Touma, acting as a swordsman from the Sword of Logos organization, who have been protecting these "books imbued with power" since ancient times! After taking him to the Northern Base of their organization, he starts to reveal some unbelievable facts to Touma!

After the young man on a lion is a young man on a flying carpet. The name of the young man who speaks to Makoto Hiba intimately is Fukamiya Sage. The wise man was a childhood friend of Makoto Toba. Do you know what Makoto Toba's dream is, what happened 15 years ago? In addition, a new swordsman appears in front of Makoto Toba and Rintaro who rushed to the incident. Ryo Onoe, a clay swordsman and Kamen Rider Buster who carries a large sword and daringly cuts Megiddo. Onoe was a swordsman with a child.

Despite defeating Megiddo, the incident is irreversible. Onoe, who is worried about his son Sora, promises that Makoto Hiba will definitely help Sora. However, that word touches Onoe's reverse scale. "Do you understand my parents' feelings!" Still, Makoto Hiba leaves behind saying that he will keep his promise. Tells that there is a wise man on Onoe who is not frustrated. The mystery of Megiddo, and where did the people disappear? Makoto Toba and Rintaro desperately think about it. On the other hand, Mei who feels responsibility takes a ridiculous action

The Swordsman of Darkness, Calibur appears before the other swordsmen! He himself betrayed the Sword of Logos 15 years ago, and triggered a familiar incident of Touma's! The swordsmen are taken by the sudden appearance of Calibur! Meanwhile, Kento Fukamiya quietly ponders alone... Touma makes his way towards another incident while concerned about Kento's quiet state... Furthermore, the sudden appearance of Calibur once again triggers something deep within Kento...!

The swordsman of darkness, Calibur turns out to be Kento's father! However, Touma is still unaware of this fact! Just then, a new swordsman appears before Touma! Ren Akamichi, a hot-headed individual compared to Touma, is significantly younger than him too! Ren, who seeks out Kento's recognition, discovers that Touma is his childhood friend and a fierce rivalry then emerges between the two! Meanwhile, Storius and Desast make their move upon Touma, while Rintaro and Mei encounter Zooous...!

Rintaro returns to the library of the Sword of Logos with several wounds on his body, but without saying a word! Meanwhile, Touma, who is desperate to find the key to unlocking the seal of his sword in Avalon, finds some clues to its location after searching through books in the Sword of Logos library! Simultaneously, Calibur is also making his way towards Avalon! Just what lies in Avalon, and who or what awaits there?! How does one even get to Avalon in the first place?! Meanwhile, in the real world, mysterious cases of three cities disappearing at once suddenly emerge! When Ogami and Ren arrive at the scene, Legeiel, Zooous, and Desast also appear! Not to mention Storious also appears, and Mei is in danger! What exactly is going on around here...?!

Rintaro was able to harness a new power from within Liberation, and rescued Mei! Meanwhile, Touma arrives in Avalon and retrieves the King of Arthur Wonder Ride Book, but for some reason its expression is reluctant! It possesses a great power that no one can handle, which is why it is sealed! Can Touma master this kind of power? Calibur suddenly attacks a doubtful Touma, while Ogami who shows up to protect him doesn't appear to be in the same condition he used to be...

Touma has mastered the power of King Arthur, so Calibur and Storious try to counteract this by creating a new Wonder Ride Book! It requires the power of Jaaku Dragon, multiple Alter Ride Books, and the Wonder Ride Books of the other swordsmen to complete! Calibur approaches Touma with a special Megid created by Storious, while Blades and Espada have their Wonder Ride Books stolen after Calibur's vicious attack! While the swordsmen are in the midst of imminent danger, a man shows up wielding a new sword in his hand! Furthermore, there's a mysterious woman who suddenly appears at the Northern Base...!

It was Kamen Rider Slash, the sword-smith of the Sword of Logos who took a Wonder Ride Book stolen by Calibur and helped out Saber and the others who were in trouble! He fought off Calibur as a new swordsman, but his Wonder Ride Book remained stolen. Meanwhile, Touma gets caught up in Calibur's words: "Things aren't always as they seem". Sophia is also skeptical that Calibur is actually Kento's father, Hayato Fukamiya. Meanwhile, Kento thinks of his father and continues to ponder the situation further. Touma and Rintaro notice this, but Kento remembers what his father did 15 years ago, and tries to distance himself from the others. All the while Reika, a messenger from the Southern Base, makes contact with Kento! On the other hand, Calibur and Storious are one step closer to completing a new Ride Book! The young swordsmen challenge Calibur once again, while the clashing of their swords are mixed with the clashing of their feelings...

Kamen Rider Calibur, who betrayed the Sword of Logos 15 years ago and joined with the Megid, has his identity revealed as Daichi Kamijo, the previous Flame Swordsman! Kento's heart, struggling to reconcile his feelings that his father could have actually caused that chaos 15 years ago, feels greatly disturbed! Touma's shouts of concern do not reach Kento's heart, as he wonders "Could my father really have betrayed us?" and "Where is he now?!" Kento confronts Rintaro after he tries to calm him down over his feelings with his father, and his new obsession with Kamijo. Meanwhile, several locations in the city start vanishing all at once, as Touma and the others face these incidents one by one! But Kento...!

Kento finds himself fallen before Calibur's new power as he confronts Daichi Kamijo about the event 15 years ago and the whereabouts of his father! Just then, it was Rintaro who took the attack for him, as Rintaro fell to the power of Calibur's sword! Meanwhile, six locations in the city are being transported to the Wonder World simultaneously, and as the swordsmen defeat two of the Megiddo there, they notice the effects don't disappear, and pillars of light with a ring at the top suddenly emerge from the ground! The remaining Megid are still inflicting damage on the city! With the absence of Sophia, Touma decides to continue fighting, knowing now that this is some sort of trap. However, it was Kento who recognizes this effect and remembers something important! The key to all of this lies 15 years ago! Kento decides to go to the place where he made his promise, to reconcile his feelings from long ago...

Kento confronts Calibur alone, holding on to the thoughts he's harbored for the past 15 years, however, he falls before Calibur's overwhelming power! Meanwhile, in the city there stand five pillars of light with five rings above them in the sky! Touma, whose memories have returned, lets the others know that they are attempting to recreate the same event from 15 years ago! Once the sixth pillar emerges, a door will form in the center! The decisive battle rests in the sixth section of the city as the swordsmen rush there to urgently stop Calibur! However, Calibur uses the power of his own sword to activate the last pillar! At this rate, the world will... Just then, a mysterious aura starts to spread in the sky above...!

Calibur was able to open a book-shaped portal to a world possessing a great power within! However, during that same battle Touma gained a new power and defeated Calibur! Despite this, the price he had to pay was too high as Kento was swallowed up by the darkness and disappeared! This battle isn't over yet! The other swordsmen take the Raimeiken Ikazuchi and the Tri Cerberus, Needle Hedgehog, and Lamp do Alangina Wonder Ride Books left behind to take into the final battle. Their feelings instilled within their swords...

Touma fights on carrying the will of Kento on his shoulders! Rintaro also gained a new power, but in the midst of their fight the door to a great power was opened! Calibur disappears into the door with Saber chasing after him! Just what is the purpose that Kamijo was telling them about during their battle? Meanwhile, the other swordsmen still on our world were informed of something truly terrifying by Storious! What lies beyond that door? What is this great power? Not to mention, if all of the pillars are shattered, the door will close and Touma will be trapped on the other side forever!

Touma has defeated Calibur and saved the world with his friends! However, Kamijo left a new mystery moments before his death! The end of the world has already begun! Not to mention that Luna is a special being who connects both of their worlds! And a true enemy within the Sword of Logos was involved in the incident 15 years ago! Unlike Kamijo, Touma vows to reveal the truth with his friends. However, the Southern Base messenger, Reika Shindai, was operating from behind the scenes! Just then, Rintaro and the others appear in front of Touma telling him "Give us your Seiken and Wonder Ride Book." Touma is confused because it was just yesterday when he fought alongside them as allies! Just then, a man wearing a hood appears. "I'm the sword who protects the world!" It was in that moment, when this man suddenly transforms...!

Touma, who had to fight his own friends, is in a state of doubt, just when Yuri, the Sword of Light appears before Touma! Meanwhile, Rintaro and the others don't think that Touma will truly betray them despite their previous conflict. However, Reika tells them to hurry up and collect his Seiken and Wonder Ride Book! Meanwhile, the Megid are trying to make a new book using humans! Touma is shocked to learn that the Megid who was attacking the city, was originally human! Yuri then tells a lost Touma, "If you want to protect them, then slash at the enemy. For that is all a swordsman can do." The Megid soon appears again as Touma heads for the direction of Mei...!

Touma struggles to find a way to save Yuki after being turned into a Megid, and can only protect her from Yuri who tries to vanquish her! Touma asks Yuri about how he became a sword in the legendary battle centuries ago, and proceeds to ask for his resolution, for if they don't move quickly, Yuki will become a complete Megid! Rintaro and Tetsuo appear before Touma, who is impatiently searching for an answer! The two came to talk, but a Megid suddenly appears before them as Rintaro immediately transforms and tries to defeat the Megid! At the same time, Touma also transforms into Saber...!

Touma's determination is acknowledged by Yuri, who offers to cooperate. Yuri tells that the current guild is trying to bring back the Almighty Book, where misuse of that power puts the world at great risk. The enemy is not limited to just the Megid, but the true enemy of the guild as well. Meanwhile, having protected the Megid causes concern to the other swordsmen. Ryo and Tetsuo are worried about Rintaro and Ren being on the verge of an outburst. Tetsuo takes Yuri's words, the Sword of Light, to heart: "There is no justice within the current guild." Then, Tetsuo tells Ryo that he will cross swords with them himself to uncover their true intentions. Meanwhile, Storious uses a high school student to create a new Megid.

Touma witnesses what a real swordsman should be before Tetsuo "Someday, I will..." However, his attention turns towards saving Shingo who has been turned into a Megid, while he is facing problems with his form appearing and disappearing very suddenly. Meanwhile, at the Southern Base, Tetsuo tells the others that Touma was telling the truth about that human turning into a Megid. However, Reika is suddenly forced to make a ruthless decision as she tells Ren that the Sword of Lightning is still in Touma's possession. The battle between Saber, Saikou, the Megid, and Legeiel is joined by the clashing of swords against each other, resulting in a great melee. Just then, Yuri sees Touma trying to save Shingo while still being hurt.

Mei warns Touma of all of the recently missing people and after immediately heading out towards the scene, Touma learns that there were many more victims besides just Yuki and Shingo alone. Touma and Mei are saddened by the fact that there were people who they couldn't save. Meanwhile, at the Southern Base, Tetsuo declares that he will bring the Sword of Flames back to the guild, staking his pride as a swordsman on the line in order to prove his loyalty to the guild. He recalls feeling something akin to when his grandfather told him about the myths of the Seiken. The battle between the swordsmen and the threat of a new Megid are quickly gaining on Touma. Around that time, Yuri, who was told of the possibility of recovering his swordsman's body, was paying a visit to Tassel.

At the Southern Base, Tetsuo's departure has caused tensions within the guild as Ryo blames Reika due to her disdain towards Tetsuo. On the other hand, Touma, whose friends have returned for the first time in a while, is starting to enjoy himself for once. Just then, his Sword of Flames begins to glow brightly, giving Touma the sense that soon he will be able to separate humans from the Megid. Meanwhile, Storious implants the new Megid's Alter Book, who was previously defeated, into someone else. This person being the twin sister of their first victim, Remi. In the midst of their search for Remi, Ryo stands before Touma and Mei. What could he possibly want from them?

Touma and the others ask Tetsuo about the current state of the Southern Base who tells them that none of them were allowed to speak with Master Logos, and that all communication is carried out through Reika. Could Reika be the true traitor of the guild? Mei suddenly remarks, "Such a great Master should be able to talk to people face to face, don't you think?" While Tetsuo is reluctant, Touma and Yuri are enthusiastic, as their operations regarding the Southern Base get set into motion. Meanwhile, Storious plans to invade the Southern Base in order to steal a forbidden tome for himself as he, Touma, and Tetsuo are all found within the walls of the Southern Base, each with their own motivations. Touma follows the trail of a mysterious young man who leads him to Storious clutching the forbidden tome. This tome contains so much power within it, that even Storious himself is unable to control it all.

The tome that Storious stole from the Southern Base's Forbidden library has fallen into Touma's hands. Its power was so strong that it made him go berserk. Reika informs the swordsmen of this development and seeks to retrieve the book at whatever cost, even if it means striking down Touma in the process, which Ryo strongly opposes. Reika informs Ryo that these orders come directly from Master Logos himself, and although Ryo struggles with the nature of the request, he nonetheless accepts the verdict. It isn't long before Touma approaches him once again. "Come at me with everything you've got!", exclaims Ryo who stands against Touma in a fierce fight as Mei and Sora stare at the ongoing battle. Who shall emerge victorious? Meanwhile, Legeiel, who had been completely devastated by Primitive Dragon's vicious attack, decides to focus his attention on another vengeful fight against Saber..

Touma goes on yet another rampage as Primitive Dragon. However, Rintaro had his Wonder Ride Books stolen by Primitive Dragon, so it was Saikou and Calibur who were the unlikely ones to save Mei's life in the nick of time. Touma suffers a dreadful nightmare that he will unknowingly kill his friends in the midst of another mindless rampage as Primitive Dragon. He's concerned that if he doesn't do something about this now, he will be fighting his own friends more than the Megid and the traitor in the Sword of Logos. Meanwhile, Rintaro has an audience with Master Logos where he is reminded of just how dangerous Touma is right now. It isn't long before Mei reaches out to Rintaro to meet with her and Touma. It's been a long time since they've seen each other again.. It was just then that Ryo and Tetsuo were suddenly attacked by a new swordsman within the Northern Base.

Calibur's identity turned out to be Kento, who should have died. Despite this revelation however, Kento suddenly leaves telling them he will seal all the Seikens to save the world from destruction. Believing that they can fight together again, Touma and his friends try to engage Primitive Dragon who has caused Touma to go berserk more than once. Meanwhile, Ren is glad to hear that Kento has resurrected, but is told by Reika that he is an enemy of the guild. So just what happened to Kento? This is the beginning of the battle over the Great Book, Yuri tells them, being the first owner and keeper of the power of the Sword of Shadows. Yuri confronts Kento alone, but it eventually drags him into a battle against him. Just then, he starts to make his move.

Kento said that he saw the future. Touma, who desperately tries to talk to him, ends up fighting against his saying "This is the end of your story", that has now become "I must seal all the Seiken to save the world from destruction", and in its wake, Kento seals Tetsuo's Onjuuken Suzune! Touma's story is still far from over as he starts to contend with his new feelings. However, his first step has to be dealing with the effects of Primitive Dragon. To do so, Touma attempts to make contact with the mysterious boy, who keeps appearing before him whenever his mind is consumed by Primitive's rage. Meanwhile, Legeiel, who burns for revenge against Saber, appears in a powered-up form, overwhelming both Buster and Saikou. Yuri, who believes in Touma and continues to fight, also looks upon Kento and Rintaro's decisions as well.

The Primitive Dragon who forced Touma out of control so many times before was actually a lonely dragon who had lost all of his companions. Touma decides to continue their story, and in doing so forges a new Wonder Ride Book known as Elemental Dragon and defeats the revenge-obsessed Legeiel once and for all. Rintaro, who witnessed these events as well, makes a sudden decision in the moment. Then, Ren leaves the guild in search of Kento as he intends to face him alone. Meanwhile, Mei is asked by her editor-in-chief if Touma can make a sequel to his masterpiece "Lost Memory". When presented with this, knowing well that she wouldn't take no for an answer, Touma decides to recall the story from the beginning. Ren confronts Kento directly. What will their encounter bring to the fold? Lastly, a mysterious man appears at the request of Master Logos.

Rintaro who decided to finally make his move, advances. He tells Mei that he will return to Touma, but before that, he goes to face Master Logos alone to determine the truth as a swordsman. Upon hearing this, Touma and his colleagues think that Rintaro is in danger and try to rush the Southern Base. Rintaro meets Master Logos and asks him of his true intentions. What is the true purpose of Master Logos? A new swordsman stands before Rintaro. His name is Ryoga Shindai, also known as Kamen Rider Durendal. He notices as the Seiken from that very same swordsman starts to point towards Rintaro.

Rintaro is back in the Northern Base. The other swordsman are furious at the realization that the true traitor within the guild is in fact Master Logos. Rintaro apologizes before his friends as they warmly accept him back into their group. Mei, who looks upon this scene with a smile, thinks about what she can do to help contribute, as she starts to fabricate something of her own. Meanwhile, Storious and Zooous create a new Megid that targets Rintaro and his Seiken since he's rejoined with the other swordsmen. The Megid appears and Rintaro and Touma rush to the scene. Rintaro is amazed to see just how much Touma has grown as a swordsman, and is looking forward to seeing what he can do as well. The Megid is targeted by the swordsmen, but as they approach they start to realize that the Megid is actually Mei.

Rintaro was overwhelmed by his inability to save Mei. Being shaken by the strength of his own convictions, he flees from the Northern Base. Just then, the Megid that has taken Mei reappears and the growing fear that they may be unable to free her intensifies. Saber fights the Megid alone, and Mei is about to be separated from it, but her separation is still incomplete. Still, once again, Zooous stands before Saber, keeping him from accessing the Megid. Saber is facing a two-on-one battle, and occasionally the Megid reverts back to Mei and vice-versa mid-combat. Can they really save Mei in time? What will become of Rintaro?

Rintaro has renewed his faith in himself after much conflicted doubt. Thanks to the unwavering trust of Touma and Mei, they continue to push on forward without giving up the fight. Meanwhile, Master Logos starts to make his move. His goal is to extract the secret power that resides within the Northern Base. An arrow shot by Master Logos destroys the barrier protecting the Northern Base as both Reika and Ryoga appear to confront the swordsmen. Plus, Zooous and Storious were also simultaneously invading the Northern Base as well. The four swordsmen within fend off the attacks from two opposing enemy factions. Touma and Yuri confront Durendal and Sabela, while Rintaro and Ryo face off against Zooous and Storious, two of them who still have a personal score to settle.

Rintaro gained new power through the Almighty Book stored within the Northern Base. However, Reika stole the Onjuuken Suzune, Dogouken Gekido, and Raimeiken Ikazuchi, and their respective Wonder Ride Books as Master Logos' goal involves both all the Seiken and their Wonder Ride Books to be gathered. Touma and the others start to move, considering that Ren and Kento could now be potential targets. Rintaro is accompanied by Mei and Yuri, who are trying to protect Rintaro's newly acquired power. Meanwhile, Touma decides to visit Kento alone as they both reunite and talk for the first time in a very long time. However, it isn't long before Master Logos himself appears before them.

Touma and Kento came face to face with Luna who appeared in front of Master Logos. Luna disappears suddenly, but Touma is exhilarated by the knowledge that Luna is alive, while Kento remains confused as to what occurred. Meanwhile, Master Logos opens a new forbidden tome, which contains the soul of the Immortal Swordsman himself, Bacht. "Where there are people in the world there will be those who seek power, generating endless conflict to maintain it. Eventually, everything will return to the nothingness." Bacht, Kamen Rider Falchion, leads successive attacks against the swordsmen, one after another, as Yuri tells the others all about Bacht's past.