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...

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.

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

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

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...

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