After the interstellar war, the earth was reduced to ruins, and mankind was divided into hostile "pure-blood faction" and "mechanical transformation faction". {Lei} was once a mecha pilot with great achievements, but lost his left arm and right leg in the final battle. He was forced to undergo mechanical transformation and became an "alien" in the eyes of the pure-blood sect, living in seclusion in the ruins. When the remaining alien fleet comes back and wants to completely destroy the earth, the two factions are still fighting each other. The rusty old mecha "Iron Bone" was activated again. Using his half-human, half-machine body, Lei broke through the shackles of the prejudices of the two factions and persuaded his former compatriots to join forces while pursuing the secret weapons left over from the interstellar war. On the ruins, the mechas roared and the remaining soul burned with blood. He will eventually become the last line of defense to protect the earth.
