Kill Devil is a Japanese movie about a group of juvenile delinquents in the year 2025. The juveniles are host to a "murder gene", and are sent to an uninhabited island by the government so that they can be rehabilitated. The government studies the causes of the gene, and implants an experiment on the juveniles called a "Tag". The Tag gives the juveniles murder impulses and memory loss, and both boys and girls start to brutally kill each other.
The story begins with a regular day with Takumi, Mari and Keitaro, which suddenly turns into a musical number thanks to a mysterious new boom box created by Smart Brain. As it turns out, Yuji, Yuka and Naoya have the same boom box and are greeted by a rapping Smart Lady who reveals that it's part of a new plan by Smart Brain to invoke people into singing all over Japan. The reason: To get the three Rider Belts back!
