The Metal Men battle against United States soldiers, in Antarctica. Three weeks prior, the army base at McMurdo Sound had been attacked by a Cadmium robot. The soldiers were able to repel the attack, only to be repeatedly attacked over the next six days. Always by a different robot. First Tungsten. Then Barium. Then Chromium. With their radio out, and their stress level near the breaking point, the men of McMurdo base tracked their robot assailants into the arctic wilderness. Where they came upon the Metal Men. A lucky bazooka shot takes out Iron's temperature regulating arm band. Iron immediately freezes. The soldiers target the Metal Men's arm bands, incapacitating all of them. The next morning, the soldiers are preparing to destroy the Metal Men, when the radio operator receives an urgent message from General Henry Caspar.
The commanding officer, Major Admundson, is informed that the Metal Men are on their side. The order is given to thaw the Metal Men out. Back on their feet, the Metal Men explain their presence. They had been in Venice, attempting to retrieve a billion dollars in United States currency, paid to their inventor, Doctor William Magnus. The money was protected by Chemo, who hurled the vault into orbit. Most of the Metal Men had been destroyed, while stopping Chemo from razing Venice. Magnus had repaired the team, back at their laboratory headquarters. Magnus determined, using a super computer, the likely place the vault came back down to Earth... Antarctica. The team flew to the coordinates in their Jetaway, but were immediately shot down upon arrival.
The Metal Men quickly molded themselves into a shelter for Magnus, to protect him from the merciless cold. Lead spied another robot barreling towards them. It's designation, "Liquid Oxygen". Liquid Oxygen grabbed Magnus. Tin leapt at Liquid Oxygen only to be flash frozen and shattered. The Metal Men were conducting a search when the military forces attacked them. Not far away, Magnus is confronted by his true abductor, the Plutonium Man. Magnus' robot doppelganger had been destroyed in combat with the Metal Men. Or so Magnus thought. In truth, the Plutonium Man had been converted into raw energy. Splitting his energy form in twain, allowed the Plutonium Man to return to his former state.
The second robot was no more than a slave, but one that could alter it's atomic structure into any element. The Plutonium Man sent his robot servant to attack McMurdo Base. With the soldiers panicking at the appearance of any robot, the Plutonium Man knew they would attack the Metal Men on sight. As Magnus' desires are darkly mirrored by the Plutonium Man, the radioactive robot made it's own play for the vault. Tearing the vault door from it's hinges, the Plutonium Man inadvertently incinerates the billion dollar ransom. Having tracked the Plutonium Man's robot servant by it's radiation signature, the Metal Men, along with the United States Army, swarm the Plutonium Man's position. Platinum binds the Plutonium Man, but not before he can issue a change command to his servant.
The robot becomes Liquid Helium, and begins flash freezing the soldiers. The Plutonium Man melts Platinum, as one of the soldiers blasts him with a laser cannon. The laser merely intensifies the Plutonium Man's power, allowing him to instantly melt Iron. Lead smothers the Liquid Helium robot, causing it's core temperature to reach critical mass. As the robot melts down through the arctic bedrock, Gold slingshots the Plutonium Man into a deep crevasse in the ice. The burning robot touches off an earthquake, that seals the fissure about the Plutonium Man. With the help of the United States Army, Magnus is able to collect the remains of the Metal Men, and rebuild them in his laboratory. Platinum, who, due to a faulty responsometer, had been overly affectionate towards her fellow Metal Men, resumes her ardor for Magnus, upon her reconstruction.