Before the birth of the Igarashi children... A dying and seriously injured man was brought to the scientific research organization Noah. The man, Junpei Shiranami was transplanted with Giff's cells into the heart by Masumi Karizaki and survived. He was forced to become the strongest Devil hunter and given the Vail Driver. Junpei, whose parents were killed by the red Devil, becomes Kamen Rider Vail with revenge on his mind, continuing to fight the Devil...