Complex sentence: Kill Devil is a Japanese movie about a bunch of juvenile delinquents with the murder gene in the future of 2025, who were sent on a uninhabited island by the government so that they can be rehabilitated.
Split into simpler sentences: 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.