25 years ago, before Ikki, Daiji, and Sakura were born, a dying and critically injured man was brought into Noah, a scientific research organization. That man, Junpei Shiranami, was given a heart transplant by Masumi Karizaki and recovered. He is then given the Vail Driver and forced to become a powerful demon hunter. Junpei, whose parents were killed by demons, becomes Kamen Rider Vail with revenge in his heart that drives him to fight... The duration of the special takes place 25 years before the events of the series. The first episode's opening scene takes place in an unspecified time period in the present day.