The self-styled, modern day reincarnation of Genghis Khan appears before a panel of evil scientists, in a hostile foreign country. Tasked with destroying the Metal Men, the boastful villain demonstrates the power of his laser sword, by decapitating a series of Metal Men figures, with a single slashing motion. The Metal Men are performing for a group of children, outside of Doctor William Magnus' sprawling laboratory complex. Suddenly, the faux Genghis Khan leaps out, and decapitates the entire team, with a single swipe of his laser sword.

The children are horrified, until Platinum's severed head begins to speak to them. To soothe the children's fears, Platinum recounts the origin of the Metal Men. A gargantuan, radioactive manta ray had emerged from it's eons long slumber in the arctic ice. The best efforts of the military had proven futile in destroying the creature. As a last resort, Colonel Casper approached Magnus, in the hopes that his scientific genius could win out over the creature. As luck would have it, Magnus had just competed work on his Metal Men. A half dozen robots, each endowed with the amazing abilities of the element from which they took their individual names.

The Metal Men were enlisted in the fight against the creature. At first, Magnus forbade Platinum's participation in the mission. Platinum, however, quickly proved her mettle to her creator, and was allowed to share the risks with her "male" peers. Traveling in their Jetaway, the Metal Men quickly located the creature, and engaged it in combat. Lead was molded into an enormous cannonball, which Tin then coated for added durability. Iron hurled Lead and Tin at the creature, only to see them reflected back at the Jetaway. Magnus is barely able to right the craft, before it crashed into the ground below.

Tin extricated himself from Lead, and charged the creature. The littlest Metal Man was instantly destroyed by a radiation burst from the creature. Lead hurriedly threw up a shield to protect Magnus, and the remaining Metal Men. While Platinum and Mercury shored up Lead, Magnus tasked Iron and Gold with capturing the creature. The creature, however, proved too strong, and dragged Iron and Gold off into the sky. There, the creature destroyed them with another radiation blast. Piloting the Jetaway above the creature, Magnus had Mercury leap onto it's back.

Mercury spread his body out across the creature, completely coating it in Mercury. Magnus' tactic to cut off the creatures air supply, however, failed, as the creature did not actually need to breath. Realizing the creature was actually living off radiation, Magnus had Platinum bind the creature, long enough for Lead to coat it with his body. Cut off from the radiation that powered it, the creature plummeted into the sea, where it was sealed within a deep oceanic trench. Magnus collected the Metal Men's remains, and returned to his laboratory, where he reconstructed them.

At the end of Platinum's tale, the other Metal Men hurriedly collect their heads. In their haste, however, each Metal Man has attached the wrong head to each of their bodies. Magnus has managed to stay alive long enough for the Metal Men to come to his rescue. The false Genghis Khan, however, cuts the majority of the team to ribbons, before they can actually act. Only Platinum and Nameless are left standing. Nameless grapples with the swordsman, attempting to wrest the sword from his hands. The sword falls to the ground. The impact causes the laser to discharge, into the swordsmen's face, killing him. The battle ended, Magnus, once again, sets about reconstructing the fallen Metal Men.