The narrative begins with the enigmatic Imagin hijacking the DenLiner, plunging the time-traveling train system into chaos. Led by the rogue, memory-stealing Imagin named Negataros, this faction of villains seeks to alter the timeline for their own malicious ends. Negataros possesses the unique ability to manipulate memories and command lesser Imagin, posing a massive threat to the fabric of history. Simultaneously, modern Tokyo is gripped by a wave of bizarre thefts orchestrated by Negataros’s gang, drawing the attention of the police and legendary Kamen Riders.Ryotaro Nogami, still housing the chaotic yet lovable Imagin—Momotaros, Urataros, Kintaros, and Ryutaros—transforms into Kamen Rider Den-O to investigate. Alongside him is the young, eccentric violin maker Wataru Kurenai, who fights as Kamen Rider Kiva. Initially, the two heroes struggle to coordinate their vastly different fighting styles and personalities. Ryotaro is proactive and driven by protecting human bonds, while Wataru is more reclusive, burdened by the heavy legacy of his Fangire heritage and his duty to protect humanity from his own kind.As
the investigation deepens, the plot thickens when the villainous Negataros captures the DenLiner, stranding Ryotaro’s crew in the past and cutting off their access to their primary base of operations. To make matters worse, Negataros uses stolen memories to manifest a powerful, monstrous army, aiming to merge the timelines and establish a dark empire ruled solely by Imagin.Driven by desperation and an unwavering sense of justice, Ryotaro and Wataru put aside their initial friction and forge a formidable alliance. With the help of the Owner, Naomi, and the fierce detective investigations led by the
police inspector, the heroes track the DenLiner down to an abandoned railyard where Negataros plans to execute his final temporal shift.A massive, action-packed showdown ensues. The Den-O crew utilizes their various forms—Sword, Rod, Axe, and Gun—to dismantle the grunt Imagin, while Kamen Rider Kiva unleashes his powerful Emperor Form to counter Negataros's heavy hitters. In the climax, Ryotaro and Wataru combine their strengths in a breathtaking display of teamwork. Channeling their ultimate energies, they execute a devastating dual Rider Kick that obliterates Negataros, shatters his stolen memories, and restores the timeline. With the DenLiner recaptured and peace finally restored to both eras, the heroes part ways, leaving behind a legacy of unlikely camaraderie and a preserved future for humanity.