Based on

Movies like Kamen Rider Den-O: Singing, Dancing, Great Training!! (2007)

Ryotaro Nogami, Kohana, Momotaros, Urataros, Kintaros, Ryutaros, Deneb, and Sieg join in on a series of exercises to get Ryotaro into shape so he can fight. Unfortunately, the Spider Imagin, the Wolf Imagin, and the Anthopper Imagin interrupt the exercises, Ryotaro becomes Kamen Rider Den-O Liner Form to use his training against the evil Imagin!