Baku Yorozu is an invincible agent who uses his lucid dreaming ability to brilliantly rescue Nemu, a national celebrity, and complete difficult missions in his dreams. One night, Baku is suddenly attacked by a monster, the Nightmare. In his lucid dream, Baku fights against invincible foes, but for some reason, he is unable to defeat the Nightmare and runs away. Baku, cornered, encounters a mysterious person, who entrusts him with the Zeztz Driver and Capsems, and he transforms into Kamen Rider Zeztz!

In a dream, Baku somehow becomes a fugitive criminal. When he encounters the Bomb Nightmare, he transforms into Zeztz, but the Nightmare escapes. One night, Baku is suddenly summoned by Zero, who gives him an order to "infiltrate other people's dreams and prevent the Nightmare's nightmares before they happen." This means that he has to stop that bomber... Baku's mission to protect his "dream master" begins!

"To stop the nightmare, you must find the Mind's Door in the nightmare world." After receiving an order from Zero, Baku falls asleep and infiltrates Fujimi's nightmare to find the door to his mind. However, the Bomb Nightmare causes an explosion in front of Baku's eyes. If this continues, Fujimi's nightmare will become reality!? Baku transforms into Zeztz to save Fujimi and the world!

Baku dreams that he is guarding a VIP, the father of the bride, at a wedding rehearsal. Then a man appears and tries to steal from the bride, Miyuki. Baku's protection saves the day, but is he the dreamer of the Nightmare? On the day of the wedding, Baku, who is guarding the wedding in his dream, is confronted by a Nightmare who is after Miyuki. Baku transforms into Zeztz, and with the new powers he has gained from Zero, he challenges the Nightmare to a dogfight...!?

Why is the bride Miyuki the dreamer? Baku, who continues to gather information in the real world, comes in contact with Miyuki standing in front of a large tree in the park. He learns that Miyuki has a memory of the tree that could change her life. In the dream world, Baku finds Miyuki's Mind's Door and sees an unexpected scene behind the door. The Crow Nightmare appears again and attacks Miyuki and everyone else!

Baku is assigned a new mission: escape from prison. Baku tries to escape with Nem, Masumi Bijogi and Reiko, who are trapped in a prison nightmare, but their way is blocked by various traps. And what secret is hidden in the relationship between Nem and Bijogi? Nox appears in front of Baku and eerily says, "This is an inescapable prison of death." Will Baku be able to carry out his impregnable mission?

In a dream imprisoned within a prison, the dream master, Bijogi, took Nem and vanished. Puzzled by this bizarre behavior, Fujimi and Nasuka reveal a certain "cruel truth" to Baku. After learning everything, Baku returns to the dream world and takes on the mission anew to save Bijogi and Nem. But once again, Nox stands in Baku's way...!

Baku infiltrates the traditional restaurant "Royal Shirogane" in a dream to carry out a mission to destroy a biological weapon. Right before the wary Baku's eyes, Chef Shiomi, who had tasted the owner-chef Sannoh's dish, collapsed. Upon waking, Baku visits Sannoh's restaurant, where another unexplained food poisoning incident occurs. Could it be a biological weapon again? What is the true nature of the nightmare...!?

What is the nightmare Chef Sannoh desires? Baku finds a clue in the words of Shiomi and others in the real world, discovering Sannoh's third Mind's Door in a dream. Peering inside...! While Fujimi and the others scramble to stop the summit meeting, Baku transforms into Zeztz and collides with the Poison Nightmare. But then, Nox reappears once more...!?

Baku, tasked with the mission "Get back the national secret", infiltrates the home of art collector Atsumi in a dream. A theft occurs involving a famous painting from Atsumi's collection, and Baku suspects state secrets are hidden within that painting. However, as Baku pursues the culprit, Nox appears and warns him, "Knowing too much will destroy you." The next instant, Baku is struck by a blow from Nox's weapon...!?

The masterpiece stolen in the dream was corroded by the Nightmare. The national secret hidden within the painting would remain unrecovered if this continued... Baku was disheartened, but Zero rebukes him with an unusually stern tone. Baku once again transforms into Zeztz within the dream. As he grabbed the Wonder Capsem to protect Atsumi from the Mold Nightmare...!?

In his dream, Baku becomes an employee at the Space Center. His new mission: protect Earth from an approaching giant meteorite. Time until impact: 48 hours. Upon waking, Baku informs Fujimi and Nagumo of humanity's impending doom and springs into action. Returning to the dream world, Baku attempts to avert the asteroid collision alongside Nem. But there, Nox stands in their way. Before their eyes, Nox straps on a belt, loads a Capsem, and...!

After battling Nox Knight and acutely feeling his own powerlessness, Baku, having lost his confidence as an agent, is branded unfit by Zero. Still, a casual conversation with Seiya prompts him to reexamine himself. In a dream, he discovers Seiya's Mind's Door. Armed with a new Capsem, he confronts Nox!

Baku's new mission is to eliminate his enemy, Nox. Wandering through a black hole in his dream, Baku begins to retrace the nightmare he first saw as a child. Young Baku attends a cram school. Following his movements, the cram school instructor Nox appears! Shocked by this past encounter with Nox, Baku confronts him, desperate to recover his erased memories!

What kind of organization is CODE? When Baku questions Zero, he learns that Nox was once a CODE agent. Nem reports to Baku that she sees through Nox's nightmares. Realizing everything, Baku confronts Nox once more and transforms into Zeztz using a new Capsem...!

Baku's new mission is to rescue Nem, who was abducted by a Nightmare. Zero denounces Baku as a "traitor to the organization" for letting Nox escape. Though Baku has lost trust, he scrambles to complete the mission. Meanwhile, ignoring Baku's plight, Nox confronts Zero, equips a new Driver, and loads a Capsem!

Though he lost Zero, Baku continues his mission to rescue Nem. Nurse Haru then reveals a surprising truth about Nem's disappearance to Baku. Having found the dreamer's Mind's Door, Baku begins pursuing the Wolf Nightmare. However, Nox blocks his path and transforms into Kamen Rider Nox. Baku also transforms into Zeztz, and the two Riders finally clash!

In his dream, Baku, now a high school student, must protect his classmates—Nasuka and Kureha—from the Nightmare orchestrating a death game. As students fall, Kureha takes up a gun and challenges the Nightmare to battle. Seeing Baku intervene, Kureha murmurs, "...Seven." Why does Kureha know that name...!?

Baku meets the present Kureha, now a journalist, and learns the secrets of the organization CODE. Disturbed, Baku questions his role as an agent in the fight. Nem confesses to Baku that the Nightmares might be born from her own subconscious. Comforting the grief-stricken Nem, Baku resolutely confronts the Death Game Nightmare as it attacks once more!

In his dream, Baku, now Village Person A, embarks on an RPG-like adventure with Sota, Tomoko, and the heroine Nem to defeat monsters. When Baku encounters a Nightmare, he transforms into Zeztz, but feels uneasy about the Nightmare's strange behavior... Meanwhile, Nox confronts Six, who has appeared to eliminate the traitor. He transforms into a Rider and challenges her to battle, but...!?

Are countless children dreaming the same dream? Baku, who began investigating, discovers a common thread among the children who shared the same dream. Entering the dream world once more, Baku witnesses the terrifying conclusion of the nightmare unfolding beyond the Mind's Door. The children are in danger! Baku transforms into Zeztz and challenges the Baby Nightmare to a battle, but...!?

The new mission is to defeat the Disaster Nightmare that has appeared in the real world and take Odaka's life. Feeling distrust toward the ruthless CODE, Baku questions his role as an agent. Meanwhile, Five and Six confront the Disaster Nightmare and Nox. Witnessing their fierce battle, Baku suddenly senses something amiss!?

Baku, having undone Zeztz Catastrom's transformation after successfully defeating Nox, falls into a deep sleep and enters the realm of the subconscious. There, he learns of the intense feelings Nem carried, and Baku himself resolves to take decisive action. Finally awakening from his slumber, Baku coldly declares to Minami and the others before beginning his mission. "I am Code Number: Seven. I'll carry out my mission..." What has transformed Baku into this cold-hearted man? And where is he headed?

The cold-blooded agent, Code Number: Seven, Baku, shakes off the attempts by Minami and the others to stop him and sets out to carry out his mission: "Find Nem." Baku races to meet Nem, who has awakened from her dream. Amidst this, The Lady manipulates a Nightmare to attack CODE headquarters. Then, Three appears, transformed into Lord Three...!!

Baku awakes in a hospital bed and realizes all his experiences had been a dream. But if it was a dream, why are the Zeztz Driver and Capsems here...? Confused, Baku falls asleep and reunites with Nem in his dream. Were all his experiences just a nightmare, or...!?

In his dream, Baku recounts his terrifying experiences to Fujimi, Nasuka, and Minami. Nox was also secretly listening to Baku's story when Five and Six, acting on CODE's orders, suddenly appear! The four clash, but then a new disturbance occurs!?

Under a fierce assault from a mysterious Rider who appeared out of nowhere, Baku is jolted awake from his dream. Who is this person capable of changing the future? Baku sets himself the mission to "uncover the enemy’s true identity." Meanwhile, at CODE, Zero and Three grow increasingly alarmed by the appearance of "Sieg." Who exactly is "Sieg"…!?

Tormented by Sieg, Baku approaches Nox in an attempt to uncover Sieg’s true identity. Meanwhile, at CODE, Three is considering deploying “Code: Somnia,” CODE’s ultimate weapon. Amidst this, Baku once again faces off against Sieg and declares, “I’ll be the one to shatter this nightmare,” challenging him to battle!

Baku meets Minami, who has become an agent, in a dream. Baku helps Minami with her mission to find a lost cat, but they are attacked by a Nightmare, and he wakes up. A "Black Case" has occurred in which Minami has grown a cat's tail. When Baku falls asleep again, he challenges the Nightmare to battle in order to save Minami, but...!

Minami is a CODE agent... Upon learning the truth, Baku is disappointed and furious, realizing that Minami had merely been "pretending to be family." In his dream, Minami is transformed into the Cat Nightmare once again. Baku transforms into Zeztz Catastrom and, despite knowing her true identity, attacks the Cat Nightmare...!?

"You will be eliminated by CODE..." After receiving this ruthless verdict from Zero, Baku infiltrates Zero's dream. Attacked by a mysterious black Zeztz, Baku is forced to confront a terrifying truth! Meanwhile, Sieg, plotting to use Nem, lures her into the Nightmare Prison. Terrified by countless Nightmares, Nem is cornered by Sieg...!?

Zero, his biological father, had been using his son, Baku, for Zeztz's sake. Unable to accept his own cruel fate, Baku is tormented by his inability to understand Zero’s true intentions. Will Baku be able to overcome this nightmare…!?

Sieg turned Nem’s nightmare into a prophetic dream, causing the Nightmare to appear in the real world. Witnessing people being attacked by the Nightmare, Baku puts on his broken Zeztz Driver. He loads the Capsem and tries to transform into Zeztz, but…!?

Having been revived, Baku delves into the depths of Sieg’s psyche—who is obsessed with Nem’s nightmares—and witnesses Sieg’s past firsthand. Having identified the Nightmare dwelling within Sieg, Baku confronts him once again, and the decisive battle between Zeztz and Dawn begins!

When Baku awoke from an ominous dream, the real world had been completely transformed. Determined to uncover the truth, Baku returns to the dream world, only to find that Nem was being targeted by Six. As Baku scrambles to protect Nem, Three appears and demonstrates a terrifying power...!?

After being saved by Nox, Baku is pressed to reveal the location of CODE's base, which he saw in a prophetic dream. It seems Nox intends to storm CODE's headquarters... After much internal struggle, Baku also resolves to destroy the activation device of Code: Somnia. Nox clashes with Three, while Baku faces off against Five and take back the world from CODE!

As work on the Zeztz Driver progresses, Baku is attacked by Nox, who has been tampered with by Three. Baku fights back with the Capsem in hand, but he is gradually cornered by the relentless attacks of Nox, who has transformed into a ruthless warrior. Meanwhile, in the real world, Three notices something amiss and, in an attempt to prevent the Driver’s completion, forcibly wakes Zero from his dream…!

"I will destroy CODE even if it costs me my own life..." Driven by that single-minded determination, Baku pursues Nox, who has vanished, and delves into Nox’s subconscious. Right before Baku’s eyes, Nox—having obtained a new power from the Capsem—transforms into Kamen Rider Nox. Shouting, "Vanish into the darkness!", he clashes with Lord Three, who stands in his way!

A "Black Case" has occurred, likely caused by Code: Somnia's missing Capsem. Following orders from Zero, Baku rushes to recover the Capsem. Sieg, whose fused Nightmare has awakened within him, has returned. Could Sieg be the one who stole the Capsem!? Baku transforms into Zeztz and collides with him in a massive crash!

A series of "Black Cases" has occurred in which people who have committed crimes in the real world have gone missing. It appears to be the work of the Punish Gore Nightmare, who metes out divine punishment to sinners. Even if they are sinners, this is going too far! Nox joins Baku in his attempt to stop the Nightmare's rampage. Facing their most formidable enemy, the two transform into Zeztz and Rider Nox!

Devastated by the loss of Zero, Baku is overwhelmed by a sense of loss. “What should we do now that he’s gone…?” How will Odaka respond to Baku’s question!? Though Baku couldn’t shake his doubts, faced with a reality spiraling into chaos, he awakens with a new mission. Transforming into Zeztz in his dreams, he takes on the Catastrophe Gore Nightmare!

A new Black Case involving the Punish Gore Nightmare has emerged. Baku tries to stop Punish from running amok, but finds himself in a tough fight. Unable to bear watching Zeztz struggle, Nem negotiates with Sieg to deal with Punish. She then confronts Punish herself, but just then, Sieg appears...!

The Oblivion Gore Nightmare activates the Power of Oblivion. Nem's memories are erased, and the objects and people around her begin to vanish one after another. "I don't want this to happen!" Nem desperately tries to resist, pleading with Sieg and Nox. And Baku, who tries to save Nem...!?

Having awakened with no memory of her past, Nem had become a popular celebrity, spending her busy days under the watchful eye of her kind mother, The Lady. However, an incident threatens this peaceful life: the Oblivion Gore Nightmare appears and attempts to merge with Nem. As Nem’s consciousness grows hazy, she is drawn toward Oblivion…!?

The Lady, determined to bring Nem back, uses the power of the Phantom Gore Nightmare to create a new world of illusions, driving Baku into a desperate situation. Nox’s dark powers should be able to dispel Phantom’s illusions. Having regained his memories thanks to Baku and Nem, Nox transforms into Nox Midnight Shadow and clashes with Phantom!

Although he dragged the Phantom Gore Nightmare into the darkness, Odaka remains in a deep sleep. Is he refusing to wake up of his own accord? Meanwhile, the Oblivion Gore Nightmare once again unleashes the power of oblivion. “It’s because I was born that these nightmares are happening…” To save Nem, who is suffering from this, Baku transforms into Zeztz! He challenges Oblivion to battle, but…!?

Sieg teams up with Nox to take the place of Baku, who is suffering from physical ailments, and they face off against the Oblivion Gore Nightmare. Baku, having recovered, also joins Nox and the others. He transforms into Zeztz and challenges Oblivion to battle, but around that time, Nem...!?

"Bring Nem back." Driven by strong resolve, Baku heads toward the Mind's Door, but if Nem returns, the Oblivion Gore Nightmare will also be revived. The world will be destroyed once again. Still, Baku refuses to give up. In a completely white, empty space where no one else is present, he pleads desperately, but…!?

Baku transforms into a Rider alongside Nox and Sieg. They face the Oblivion Gore Nightmare in their final battle. Even with the combined power of Zeztz, Nox, and Dawn, they cannot defeat Oblivion. Just as their spirits are about to break, Zeztz picks up a new Capsem, and then...!