Emu gives Kiriya another chance to earn his trust. Kiriya then takes the chance to finally reveal Kuroto's intentions and expose him as the Black Kamen Rider that is working with the Bugsters.

With Christmas around the corner, Emu runs against time to defeat the Salty Bugster again and save another patient, while Kiriya's investigation leads him closer to the truth, but his life is in danger when he faces Kuroto's new power.