The sky is ablaze as a comet illuminates the Earth, casting its brilliant light upon its inhabitants. However, this peaceful moment is short-lived as a colossal army of viruses storms into the world, obliterating everything in their way. Netto and Enzan utilize cross fusion to halt the invasion, but they are suddenly transported to an unfamiliar destination, where they come face-to-face with the mastermind behind the assault - Duo!