Sento Kiryu starts his new job at the Touto Institute of Advanced Matter Physics, researching the mysterious Pandora's Box. While responding to a potential Smash sighting, Sento comes across a wanted fugitive...

The Kamen Rider of Touto is now a fugitive, due to his part in saving a convicted murderer - Ryuga Banjo. Kiryu begins to see similarities in the mysterious experiments both he and Ryuga were subjected to.

The investigation into Ryuga's kidnapping leads to a man named Nabeshima. But to get the answers he needs, Ryuga must cross the border to Seito...

The mysteries of the past continue to pile up as Sento investigates the Pandora's Box disaster. In Seito, Ryuga and Sawa continues the search for Nabeshima's family.

Sento confronts Owner on his involvement with Faust. Sawa finds a lead on Sento's elusive past.

Ryuga finds the entrance to Faust's hidden base. Aiming to learn more, Sento learns of the late Katsuragi's research into "Nebula Gas".

Sento and Ryuga need to learn more about Katsuragi and his research. Setting their sights on Hokuto, they first have to get through the Sky Wall...

Now hidden in Hokuto, Sento and Ryuga try to learn more about Takumi Katsuragi from his mother, and find his hidden project data.

A debate about the nature of Katsuragi's research leads to another falling out between Sento and Ryuga. Under pressure from a backer, Faust hatches a plan to steal Pandora's Box.

As the three Prime Ministers of Japan meet, Blood Stark leads an attack on the Touto Institute of Advanced Matter Physics.

With the majority of his Full Bottles now in Night Rogue's possession, Sento reveals his trump card - a way for Ryuga to use the Build Driver.

Sawa reveals a connection between Faust, Nanba Heavy Industries, and the Touto Government. Sento and Ryuga plan to recover Pandora's Box.

A surprise call from Nabeshima lays the foundation for Sento's plan to reclaim Pandora's Box, and a chance to capture the elusive Blood Stark...

Blood Stark's identity is revealed, and Sento races against time to finish a counter-measure against him.

With Pandora's Box safely in their possession, Sento and Ryuga go after Gentoku, set on revealing the link between Touto's government and Faust to the public.

Gentoku reveals the truth behind Sento's missing memories, and the reality may tear his and Ryuga's friendship apart.

Hokuto invades Touto, looking to claim Pandora's Box for themselves. As civilian casualty numbers raise, Gentoku's government instigates Kamen Rider as their military weapon.

A new contender in the Rider Wars appears before Sento and Ryuga, somehow weilding his own Sclash Driver. Hokuto's own Rider, Grease, has arrived.

Another clash between the Touto and Hokuto Riders ends with Ryuga struggling from the Sclash Driver's effects. The Hokuto Crows are given a way to power up by Blood Stark, but there's a cost...

Soichi gives Sento the means the stop Ryuga's growing rage with the forbidden item - the Devil's Trigger. Gentoku plots a counter-attack against Hokuto's invaders.

In order to counter Ryuga's rampage as Cross-Z Charge, Sento is forced to use the Hazard Trigger. What is the cost of using this forbidden item?

Touto and Hokuto's governments have ordered a winner-takes-all battle to decide who keeps Pandora's Box. It's Build vs Grease to decide the victor of the Rider War!

Seito delivers an ultimatum to Kazumi - fight for them as their Kamen Rider or witness the death of his family. A mysterious new adversary makes his way to Touto to confront Sento and Ryuga.

Kamen Rider Rogue has revealed himself; Misora collapses inside the base.

Misora sends Kamen Rider Rogue flying through Skywall; Souichi reveals to Sento that there is a spy in the Touto government.

Seito challenges Touto to a best-of-three battle to decide who keeps Pandora's Box; Sento works to find a counter to Black Hazard's berserk state.

Kamen Rider Rogue receives the data on Build's Rabbit Rabbit form, forcing Sento to unleash Tank Tank form; Sawa's backstory is revealed while Kazumi rescues civilians; Nanba decides to not play fair, taking control of Seito and declaring war.

Despite their promises, Seito continues their assault against Touto. All this is made worse as Blood Stark completes a panel of Pandora's Box, and the Skywall begins to shift...

Blood Stark wonders how the Queen of Mars is still alive. Mysteries begin to arise as she singles Ryuuga out to become hope.

Sawa and Misora discuss what the story behind Ryuuga really is; Team Build raid Pandora's Tower in an attempt to reclaim Pandora's Box, but Blood Stark stays one step ahead, goading Ryuuga into action.

Ryuuga learns of his alien origins; Nanba takes Kazumi's friends hostage in exchange for Pandora's Box.

Souichi holds the Touto Prime Minister hostage in exchange for Sento to give him the Evol Driver.

Sento is poisoned by Evolt, who then negotiates a deal with Ryuuga for the cure.

Evolt is now in possession of Ryuuga's body and goes after Pandora's Box. Sento reaches out to Gentoku, who has the last of the bottles.

Pandora's Tower is complete and Evolt stands ready to destroy Earth. Kazumi is still angry with Gentoku for killing his friend and challenges him to a fight; Sento works on a way to harness Pandora's Box into a power-up for Build.

In order to keep Evolt from getting Pandora's Box, Bernage moves the entire cafe to a different location; Ryuuga can no longer transform and so he and Kazumi go to Gentoku for help in saving Sento.

Sento has now lost all his memories and reverted to Takumi Katsuragi; Evolt gives Utsumi and the rest of Nanba an ultimatum.

Utsumi has now taken on the role of Kamen Rider Mad Rogue; Takumi creates a new bottle to fight Evolt, but also plans to take out Ryuuga as well.

Kazumi is bummed that Evolt has stolen the bottles of his lost friends. Sento travels to his mother's house in Hokuto for answers about his father, but he and Kazumi end up face to face with a new Smash.

Sento learns that his father actually is alive; Sawa goes to find the one Faust experiment that, to their knowledge, has no relation to the Kamen Riders; Misora discovers that the Best Matches are about her.

Sento suspects that since Evolt has the Lost Bottles, he also has his father; Evolt plans to reunite Japan while Gentoku mopes over his dead father.

Sento's loyalties are questioned concerning his father; Misora makes a deal with Evolt.

Kazumi and Gentoku get caught in order to raise their hazard level; Sento builds Ryuuga a new power-up.

It turns out that Evolt is still alive, but Sento's father is able to tell him about a secret white panel in Pandora's Box.

Evolt reveals himself to the world; Sento plans to combine their world with a parallel world via the white panel; Kazumi asks for a new power up.

Kazumi uses his new weapon to battle the clones of his former friends; Gentoku does battle with another set of clones and gets help from an unlikely ally.

With Kazumi now gone, it's time for the final confrontation with Evolt.

Ryuuga has flown away with Evolt. Sento decides to go bring him back as the two worlds are about to merge.