Kamen Rider Den-O & Kiva: Climax Deka

Ryotaro and the DenLiner Police establish their role to monitor the surviving Imagin after the Den-O Pass theft. They pursue the Pink Rabbit Imagin in a high-speed car chase and clash with the Horse Fangire. The chase ends without recovering the spare Den-O Pass.

Detective Kazuya Suzuki joins the DenLiner Police and warns them of an Evil Organization rising in the criminal underworld. His information broadens the scope of the threat and tightens the investigation. The team begins coordinating with him on their next moves.

After Ryotaro's arrest spree, he and Kazuya encounter Wataru Kurenai and Shizuka who are digging for items related to a new violin varnish. A minor spat with U-Ryotaro leads to Momotaros briefly possessing Wataru. Wataru tips them off, pointing toward the Evil Organization's base.

At the Evil Organization's base, they find Yuto in the company of the leader Negataros and the man Seiya Kuroki. The scene establishes the inner circle and heightens the immediate danger the DenLiner Police face.

Kazuya attempts to arrest Kuroki but is ambushed by the Clown Imagin. Deneb and Naomi create distractions as Yuto, working undercover, tries to free Kazuya. Yuto is briefly possessed by Urataros, who woos Sarah and tries to seize the gun, but Yuto ejects Urataros and fights the Imagin as Kuroki arrives.

Back at the DenLiner, Kazuya apologizes for nearly getting everyone killed and explains his motive to avenge his father. Yuto reveals Negataros's broader plans. The DenLiner Police resolve to attack at full strength, while Wataru performs a solo violin sonata to boost morale.

Negataros begins to move his plan forward with Den-O and Zeronos and their Imagin partners in his way, while Suzuki arrests Kuroki after the DenLiner takes him and his posse away from the fight. The team readies for a major confrontation the next phase of the battle.

Negataros uses the Den-O Pass to become Nega Den-O as the fight starts. The Tarōs battle Fangires while Zeronos fights the Clown Imagin and Den-O clashes with Nega Den-O. Nega Den-O quickly gains the upper hand against all four Den-O forms.

Kiva arrives to shift the balance of power, and Den-O Climax Form joins him in a Double Rider Kick. The combined strike knocks Negataros out of his Rider form, turning the fight in the heroes' favor.

Negataros escapes in the Nega DenLiner, pursued by DenLiner, ZeroLiner, and Castle Doran. The three giants combine their powers to destroy the Nega DenLiner, culminating in Negataros's defeat.

Ryotaro takes Kazuya back in time to 1986 to see Kazuma and Otoya, giving the young detective closure about his father. The visit serves as a personal payoff for Kazuya's arc and a bittersweet ending to his journey.

Although Negataros has been defeated, Momotaros decides to keep the DenLiner Police going because being a cop is fun. After a successful patrol, Deneb asks Yuto to join the DenLiner Police, but a crooks' escape leads to a chase as the DenLiner Police and Yuto pursue them.