Here are the basics for those not already up to speed:
By 2012, humans had colonised many planets throughout the Solar System, including Mars, Jupiter, Venus and Saturn. The planet Earth however, had become polluted and overpopulated. In an attempt to save mankind, President Battaille ordered the creation of the M.A.N.T.A. ship. M.A.N.T.A. Force was an acronym for Multiple-Air-Naval-Terrain-Assault Force and was the most advanced Earth ship ever built. It was designed to work in any environment and its engine was fuelled by a substance called Thorium.
Following the successful launch of the M.A.N.T.A. Force ship, the World Government created the Red Venom to help Manta Force colonise New Earth. On Saturn however, many of the people had grown tired of living in plastic bubbles and believed New Earth should belong to them. During its test runs therefore, the Red Venom was hijacked by a group of highly skilled soldiers called the Viper Squad. Under the command of Major Vex, the Viper Squad attempted to use the Red Venom to hijack the M.A.N.T.A. Force ship, so they could be the ones to colonise New Earth.
Later the two opposing sides joined forces to fight off attacks from a cybernetic alien known as Mad Karnock, who was served by an army of robots called Karnoids. Another enemy also emerged from the swamps of New Earth in the form of the vile Stinkhorn, leader of the Stenchoids, who attempted to destroy the humans with their decomposing Stench weapons (which excreted a green compound similar to Play-Doh).