Set after the events of ''Kamen Rider Den-O'', Ryoutaro and the DenLiner gang have set up a detective agency called the who seek to keep the Imagin that survived the Junction Point in check after an Imagin stole a spare Den-O Pass from Owner while he was training. While pursuing the Pink Rabbit Imagin via car chase, they cross paths with the Horse Fangire as Den-O and the Tarōs battle them, killing the two monsters and not finding the Den-O Pass on either.