While exploring a cavern in Egypt, Cheng Sinzan discovers a leg armor plate said to be one of six pieces of the Armor of Mars, only to defeated by Laocorn Gaudeamus and his three henchmen – Panni, Hauer and Jamin – before Laocorn attaches the part to his body and destroys the cavern. In Japan, Joe Higashi defeats Muay-Thai champion Hwa Jai and reunites with his friends Terry and Andy Bogard, as well as Mai Shiranui. While being chased by a masked assailant, Sulia Gaudeamus – Laocorn’s sister – befriends Terry. After Big Bear is knocked unconscious by the assailant, Kim Kaphwan defeats him, exposing the assailant as Cheng. Sulia reveals that she has searched for Terry since his battle with Wolfgang Krauser. Sulia, Terry, Andy, Mai and Joe travel to Rhodes, where Sulia reveals that she is a descendant of Gaudeamus, a powerful warrior whose armor drew fear among Alexander the Great. One night, Alexander killed Gaudeamus, but the armor gained life after his death, and reincarnated himself as Mars before destroying a city; it was eventually defeated by four warriors. To prevent Mars from destroying cities again, the armor was broken up and hidden in different locations. On the island, the five discover a series of cave paintings that indicate that martial arts moves such as Tung Fu Rue‘s Hurricane Punch and Krauser’s Blitz Ball were influenced by Gaudeamus. Sulia reveals that she possesses healing powers due to her heritage and shares a mental bond with Laocorn. After Sulia discovers the locations of two of the three remaining armor pieces, the group divides into two subgroups in an attempt to find them.
While searching for the breast plate in Turkey, Terry, Joe and Sulia discover an ancient chamber, which was unearthed in the police station’s destruction and realize that the breast plate is in Germany’s Stroheim Castle, Krauser’s former home. Joe is sent to Baghdad to rendezvous with Andy and Mai. Attempting to find the breast plate, Terry and Sulia encounter Jamin and they escape, but Terry is seriously injured in the process. Meanwhile, Panni defeats Krauser’s former henchman Laurence Blood and acquires the breast plate. In Iraq, Andy and Mai find out that the site of the leg armor was raided when the Mongolians sacked Baghdad and brought their loot back to China. Realizing that that Tung Fu Rue knew the location of the armor piece before he died, their next lead would be Tung’s old friend Jubei Yamada. After healing Terry using part of her life force, Sulia tells him that her and Laocorn’s father was leading an expedition to find the Armor of Mars after discovering the first piece – the right gauntlet. However, a business partner killed the twins’ father and wounded Laocorn, but Laocorn killed the murderer with the gauntlet. Since then, Laocorn developed an insatiable desire to complete the armor. Hearing the story, Terry vows to fight to protect Sulia from any pain or suffering. In Japan, Andy and Mai go to Duck King‘s nightclub, where they have arranged to meet with Jubei. As Jubei gives Andy the location of the leg armor, Andy encounters Geese Howard‘s staff-wielding henchman Billy Kane, but is interrupted Hauer. After unsuccessfully trying to seduce Mai, Hauer destroys the nightclub. In China, Andy retrieves the leg armor when he and Mai are defeated by Hauer, who defeats them and steals the armor piece. The five regroup in Rhodes, where Sulia tells them that Laocorn has not found the crown – the sixth armor piece. They discover a secret chamber behind the cave paintings and use Sulia’s pendant to reveal the Dead Sea in Israel as the location of the final piece.
In Jerusalem, as Andy practices his techniques, Terry and Joe are knocked out while Mai and Sulia are cornered by Laocorn and his henchmen. Sulia agrees to go with her twin brother if he promises not to harm her friends. Laocorn, Sulia and Jamin flee, but Hauer and Panni are easily defeated by Andy and Mai. The heroes head for the Dead Sea, where Laocorn raises an ancient temple. After being defeated by Terry’s Burning Knuckle technique at the temple’s entrance, Jamin tells him that that he can save Sulia and Laocorn due to their bonds. Laocorn finds the armor’s crown, mounted on a statue of Mars, and crowns himself – causing the armor to encase him in vermeil and augment his powers and abilities. Andy, Joe and Mai join in the fight, but are overpowered by Laocorn’s newly acquired powers. When Laocorn is about to kill the heroes, however, Sulia stabs her own arm to injure Laocorn. As his abilities have become more powerful, so has his mental bond with his sister. Sulia stabs herself in the heart, causing more pain to Laocorn. As she dies, Sulia tells Terry to strike Laocorn’s breast plate. Terry defeats Laocorn and reduce his armor to four coins, which assimilate into the statue of Mars, reviving it. Realizing that the armor was using him to revive Mars, Laocorn sacrifices himself to save Mai. Absorbing the last of Sulia’s lifeforce, Terry combines it with his skills to attack Mars and eventually defeats him with his Buster Wolf technique. After escaping the temple with Mai, Andy and Joe, Terry throws his hat in silence.