While on a mission involving a Maverick attack on a highway, X encounters Vile, a mercenary Maverick working for Sigma who pilots a mechanized tank called "Ride Armor". Unable to defeat Vile, X is saved at a critical moment by Zero, forcing Vile to retreat. Zero then offers encouragement to the less combat-savvy X after the battle. X proceeds to track down and exterminate eight of Sigma's most powerful Mavericks, then rendezvous with Zero outside Sigma's stronghold. Inside the compound, X finds that Zero has been captured by Vile. Another battle ensues, ending similar to their first meeting with X at Vile's mercy. Zero suddenly breaks free of his restraints, latches onto Vile, and self-detonates, destroying his own body and the Maverick's Ride Armor. Shocked over Zero's sacrifice, X regains his strength and finishes off Vile. Zero encourages his comrade once again, and succumbs to his damage. Now more determined than ever, X fights his way to Sigma, destroys the Maverick leader, and escapes the island fortress as it explodes and sinks. As he returns to base, X reflects on the events that have unfolded, questioning Zero's sacrifice, his own decision to fight, and the ongoing war with the Mavericks. After the credits, a message from Sigma reveals that X merely destroyed a temporary body, and that Sigma's spirit lives on. Sigma then says that he would gather new, stronger bodies to do his bidding, and he would see X soon.