The Kamen Riders, known as Oni, battle man eating beasts called Makamou with "pure sound". One of the Oni, a man named Hibiki ends up having a teacher and apprentice-like relationship with Asumu Adachi. A young boy unsure of himself and is at a crossroads in his life as he transitions to high school, Asumu learns to be an adult through watching Hibiki and the other Oni as they all train together to hone their skills in fighting the Makamou and the homunculi aiding them. However, the sudden raise of Makamou numbers proves to be a prelude to an upcoming calamity.
There are those known as Takeshi who have fought since ancient times to protect people. Some of them have even dared to become Oni, to fight against the evil Makamou. Following the Oni are the boys and girls who start toward tomorrow, step by step�
After rescuing Chizu, Hibiki spends the night at the memorial where Asumu is staying. The next day, Asumu meets Hibiki out by the beach and they discuss what Hibiki does for a living. As Hibiki searches the mountain, Asumu follows him and is attacked in the woods, where he is rescued and witnesses Hibiki transform to fight the Hime and her child, a demon-spider called Tsuchigumo.
Both Adachi and Hibiki return to Tokyo where Hibiki is sent off to defeat a Yamabiko sighted at Okutama. Later on, Hibiki meets Asumu�s mother, who is ecstatic to see him. Meanwhile, the strain of studying for entrance exams begins to trouble Asumu as he worries about Hibiki and how safe he is with the type of job he has.
Asumu trails an old man whom he believes has connections to Hibiki after he sees him save a young girl. Elsewhere, Hibiki continues his battle with the Makamou who had been killing people in the forest. After the battle, Hibiki and Kasumi return to Tachibana�s sweet shop, where the Asumu and the old man are.
After a discussion with Hibiki about his plans after middle school, Asumu is reminded that he has no choice but to pass his entrance exam into Jounan, and he resolves to not see Hibiki until he gets in so he can share the good news. Meanwhile, Hibiki heads out after news that one of his comrades was injured in a fight, but can he handle an unfamiliar type of Makamou?
Ibuki, thinking Asumu is Hibiki�s apprentice, takes Asumu to where Hibiki and Kasumi are located. Hibiki and Asumu have a discussion about life and the challenges that everyone faces, leaving Asumu with a renewed passion to do well on his entrance exams. Hibiki then returns to battle the Bakegani that defeated him previously.
Excited over passing his entrance exam for Jounan, Asumu rushes to tell Hibiki the good news but is told he is training at a shrine deep in the mountains. Hinaka tells him how to get there and he sets off by himself. Meanwhile, Ibuki�s apprentice Akira arrives in the mountains and is attacked, forcing Ibuki to transform to fight a flying Makamou.
Lost in the forest, Asumu stumbles onto Ibuki�s camp where an irritated Akira tells Asumu that he will only hinder Hibiki if he continues following him around and that it would be best for him to leave. Asumu wonders just how true her words are and asks Hibiki himself how he feels about it after he arrives at the camp. Ibuki then defeats the Ittan-momen and Akira and Asumu make amends with each other.
Spring break has started and Asumu has already gotten off on the wrong foot, having missed going to the movies with his friend. He spends the rest of the day wandering around town and eventually encountering shoplifters. Meanwhile, Hibiki looks to see if his training paid off by taking down an Ooari while Ibuki and Akira track down a Makamou that seems to be a little more than they had suspected.
Asumu continues to wander through town after being a witness to the shoplifting, not really sure of himself and what to do next. Meanwhile, Hibiki and Ibuki team up to take down a very rare Makamou, Otoroshi.
A new school year has started and Asumu enters high school but still has mixed feelings on the path of life he has taken. Through all the aimless wandering he finds himself back at Tachibana�s Sweet Shop, but Hibiki has traveled out to the countryside after a call about people strangely disappearing where he faces off with new armored versions of the Douji and Hime.
After going through a false wall in Tachibana�s Sweet Shop, Asumu stumbles upon the Oni R&D room where Midori shines some light on Hibiki�s past. Meanwhile, Hibiki believes he�s discovered the secret to defeating the Armored Douji and Hime and begins to time their transformation, but he has to hurry as a Nurikabe is making its way towards the village below the mountain!
Hibiki goes to Asumu to ask him for a favor but Asumu doesn�t seem to be feeling well, and is rushed to the hospital when he collapses during class! In the mountains, after being given a power boost, an Ubume Douji goes berserk, killing the Ubume and the Hime, and proceeds to hunt down other Makamou, interfering in a battle Danki was engaging in before moving on to attack Ibuki!
Asumu is suffering from appendicitis and is rushed into surgery, as his high school life comes to a halt until he heals. Hitomi runs into her cousin while Asumu meets a man who gives him some advice as he leaves the hospital, as Hibiki and Ibuki team up to track down and destroy the berserk Douji.
Asumu returns home after spending a week hospitalized and begins his recuperation. Elsewhere, Zanki reveals that he will soon be retiring and expects his apprentice Todoyama to take his place, a revelation that Todoyama is less than pleased with. Even more, they are called to aid Sabaki at Tsukama Village, where a Yamaarashi is running rampant.
Zanki and Todoyama come to Sabaki�s rescue after being captured by the Yamaarashi, but Zanki begins to weaken and proves unable to defeat it. Todoyama takes Zanki�s place and destroys his first giant-type Makamou. As Zanki retires, Todoyama refuses to take his name, instead wanting to make a name for himself, as Zanki dubs him Todoroki, the Roaring Oni.
Kasumi and Ibuki go clothes-shopping on their day off. After shopping and during their meal, Ibuki sees a Douji and Hime pair in the city and begins his pursuit. Elsewhere, Hitomi is having mixed feelings about Asumu and Akira spending so much time together. After defeating the Douji/Hime pair, Ibuki is attacked by a Makamou that eats his disk animals as he waits for Akira to arrive with his Reppu!
Akira makes her way towards the ever-changing location of the Oonamazu but as she heads towards the battle, a puppet-type Makamou causes her to collapse under a bridge. Meanwhile, Asumu heads to Tachibana�s to drop off his notes and ends up helping Hinaka deal with the influx of customers. Finally, having tracked down the Oonamazu, Ibuki proceeds underground into the sewers to fight it for the final time�
Asumu begins his first day at Tachibana�s and discovers that Todoroki and Hitomi are related. Todoroki continues to fight the Bakegani as Kasumi notices something is wrong with him, while Zanki later arrives after he is called by Ichiro to examine a recording of Todoroki�s peculiar fighting style. Meanwhile, Hibiki practices on a dirtbike while waiting on standby�
Zanki visits Todoroki on the battlefield to question about his style of fighting while Asumu begins to have troubles at Tachibana�s and is then pulled into a conversation with Ichiro about the Oni. Hibiki later joins Todoroki in a fight against an Amikiri as Zanki makes a decision about his and Todoroki�s future.
While Hibiki enjoys a day off of fighting to run errands with Asumu, Ibuki and Todoroki are separately following two groups of Makamou that are heading towards Mount Asama. The Oni find it strange that the Makamou don�t want to fight nor do they attack humans, so just what is at the top of the mountain that draws them?
As Asumu and Mochi wait for Hibiki to return with the doctor, Akira is injured as Ibuki and Todoroki combine their strength to defeat the pair of Douji and Hime, but the Ubume and Yamaarashi are nowhere to be found. What they do find is a new, disturbing hybrid of the two Makamou and despite their best efforts, they can�t defeat it alone. Just then, Hibiki arrives as backup�
Hibiki takes Todoroki to his mountain training temple to teach him how to play the taiko so that the Oni are better prepared to deal with the summer Makamou, which are resistant to stringed instruments. Unfortunately, the training seems to be too intense for Todoroki, who loses faith. Meanwhile, Asumu is assigned the whistle in his high school�s brass band and is not too pleased with not having the chance to play the drums.
Discovering the self-multiplying Dorotabou, the Oni realize they will have to unify their powers using taiko to defeat the Makamou. As Hibiki trains harder to unleash his Crimson form, Todoroki struggles with his lack of drumming skill, but a pep talk from Hinaka might just be what he needs�
After Sabaki is defeated by a Kappa, Hibiki is sent out to finish the job. At the same time, Asumu, Hitomi, Hinaka, and Todoroki enjoy the day off by going to a water park where they run into Tsutomu Tsumura, who works at the park but has ties to the Oni world.
Everybody is out, either enjoying their day off or hunting down Makamou, leaving Asumu and Akira to tend to the sweet shop. Ibuki crosses paths with a strange couple that are dressed in full kimonos in a busy city while Hibiki and Todoroki track down a Bakeneko group hidden deep within a mountain forest.
Zanki is attacked by a white Puppet, and the damaged disks lead Hibiki and Todoroki to track down the group of Bakeneko hiding in the forest shrine. Back at Tachibana�s, Tsutomu reveals his relationship to the Oni world to Asumu and asks what he wants to do in the future.
After being beaten up for revenge by the shoplifter he stopped several months ago, Asumu loses his normal cheerfulness. Hibiki sees this and decides to take Asumu for a forest hike while fixing his damaged drumstick. Meanwhile, Eiki is defeated by an armored Douji and Hime, so Ibuki and Todoroki are called in to avenge their fellow Oni.
After his fall where he loses his phone, Asumu blames himself and Hibiki confronts the boy about being too negative and self-conscious. Meanwhile, Ibuki and Todoroki combine their efforts and battle Douji and Hime, with Eiki joining them in the battle against the Makamou, but it escapes and makes its way toward Hibiki and Asumu�s campsite�
A new boy has transferred to Asumu and Hitomi�s school, Kiriya Kyousuke, and the new boy seems to be good at everything from language to sports and makes Asumu feel boring. Meanwhile, The Man creates a new Makamou that does not have a Douji and Hime and unleashes it in the busy metropolis.
After witnessing Hibiki in battle and seeing Asumu�s familiarity with the Oni, Kyousuke declares that Asumu isn�t as boring as he thought and attempts to learn more about Hibiki, shadowing him at Tachibana�s. Meanwhile, Asumu learns more about his mother�s divorce from his father and decides to set out to meet the man he doesn�t even really know�
Kogure Kounosuke, a strong-willed weapons designer for Takeshi, comes bearing a gift for the Oni who work at the Tachibana Sweet Shop: the Armed Saber. Unfortunately, the weapon is too powerful for a normal Oni and the repercussions for trying to use it is losing the ability to transform. But when a new Douji and Hime appear more powerful than any before, the Oni may have no choice but to risk using it in battle�
After losing the Armed Saber to the Super Douji and Hime, Hibiki and Todoroki lose the ability to transform. They find out that they will regain the ability to transform in one month, but that is too long with a Makamou running amok. Kogure suggests that the two Oni undergo a special training, under his guidance, to regain their powers.
Todoroki and Hinaka�s birthday date goes awry thanks to Todoroki�s clumsiness and Todoroki feels that he doesn�t live up to Hinaka�s image of an ideal man, leading to his love life problems affecting his job as an Oni. Meanwhile, Asumu sees Hitomi give a love letter to Kiriya and wonders if this is the end of the special friendship they shared.
Todoroki finds his romantic troubles are causing him increasing issues in battle as he loses focus, and Ibuki isn�t far behind him! As Zanki tries to help Todoroki regain his confidence and get back on Hinaka�s good side, Hibiki tries to give Asumu advice after the boy falls into a depression after what he saw involving Mochida, a matter which Hibiki himself doesn�t have much experience in himself�
A mysterious Oni Armor, that gives the wearer the power of an Oni, has been stolen from a shrine. The thief uses it to attack Oni and Makamou alike; leaving the Oni wander what is the thief�s motives for using the armor. Meanwhile, Akira struggles with her hatred for the Makamou and what it means for her Oni training�
Having taken Todoroki�s transformation brace, Shuki sets out to get her vengeance on the Notsugo, despite the danger it poses to her former Oni comrades. As a result, Ibuki is tasked with the heavy burden of eliminating a fellow Oni, while Zanki struggles with who his former master has become�
When a powerful Makamou appears that is resistant to the Slaying Sounds of Ibuki, Todoroki, and Hibiki, the Oni struggle to find a measure to combat it while Ibuki also battles with Akira�s whereabouts since she departed with Shuki. Meanwhile, Asumu finds himself worrying about his self-worth after he is cut from the band as Kiriya grates on his nerves.
After Hibiki is defeated by the fearsome Yobuko, Ibuki searches for Akira, while Todoroki is severely depressed over his perceived failure with Zanki. Meanwhile, Kyousuke stumbles upon Takeshi�s armory and attempts to transform into an Oni, while Asumu and Midori attempt to escape the clutches of the Makamou before they are devoured!
A mysterious forest appears out of nowhere, causing the Oni to worry about what it could mean, and the mysterious Man and Woman also seem to be concerned with the new development. Meanwhile, Asumu believes he�s ready to become Hibiki�s apprentice while Kyousuke continues to beg Hibiki for the same thing, but both boys may be disappointed in his answer�
After Akira�s attempt at transforming, the Oni return to Tachibana�s where Asumu and Kyousuke are scolded for their attempts to become Akira�s apprentices. However, the boys are firm in their resolve to begin their Oni training, troubling Hibiki. Meanwhile, Ichirou meets with the mysterious Man and Woman, who warn him of the destruction to come�
With Orochi approaching, the number of Makamou has risen sharply, straining the Oni and their ability to handle it. With Hibiki taking Asumu and Kyousuke as his apprentices, the Oni are down even more, but even amidst the training, Hibiki rushes into battle, while Todoroki is gravely injured as he and Ibuki are overwhelmed�
After being crushed by a giant Makamou, Todoroki is rushed to the hospital, but while he survives, his prognosis is grim as he may never become an Oni again, driving him deep into depression while Zanki struggles with the situation. At the same time, Hibiki continues to train the boys, but Kyousuke�s arrogance and lack of physical skill holds him back, until he erupts with frustration at Hibiki�
Despite earlier warnings about transforming again, Zanki steps up and rejoins the fight against the growing hordes of Makamou, but it takes an extreme toll on him, but he intends to help Todoroki regain his strength no matter the cost�
Despite seeing him fall in battle, Ibuki is shocked to see Zanki appear in Todoroki�s room, but when Hibiki and Ibuki reveal Zanki�s fate, Todoroki angrily refuses to believe his mentor could be dead. As Kyousuke follows one of the boys that bullied him with Asumu on his trail, the approach of Orochi continues�
Leading the Oni to a stone with ancient Oni script on it, the Man and Woman make their next move towards preventing Orochi, but the cost of stopping it may be too much for Ibuki to bear. Meanwhile, Kyousuke becomes increasingly obsessed with becoming an Oni, with his focus on his training consuming him, while Asumu questions what it means to put your life on the line to protect others�
Coming to terms with what dying without regrets means to him, Asumu decides to walk away from his Oni training, leaving Hibiki seemingly disappointed, but with Orochi imminent, there�s no time to swell on it. Hibiki, Ibuki, and Todoroki set out to complete the ceremony, but Hibiki tricks the other Oni and escapes with his drumsticks, setting out for the purification site as the final battle begins�
Leading the Oni, Hibiki brings Orochi to a halt and purifies the earth as the ancient writings described. One year later, Asumu has moved on from Takeshi and the Oni and now interns at a hospital in his quest to find his own path to helping people. But when Mochida is captured by the Man and Woman as a new specimen for their experiments, Asumu�s path leads him back to Hibiki, Kyousuke, and the other Oni once again!
