The story before the birth of Igarashi brothers and sisters. 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 is then forced to become the strongest demon hunter and given a bail driver. Junpei, whose parents were killed by the red devil, becomes a Kamen Rider Vail with his revenge in mind and continues to fight the devil.