Casshern is based on a Japanese TV-series. In this movie, the viewer is transported into the future where the world has just seen a big war between an army from the East and an army from Europe. The East won, even though there are still rebellious factions that try to overthrow the government. The war has ravaged the world, and more than ever there is a need for peace and harmony. A scientist is conducting research into a new technology, that can rejuvante bodies and make mankind feel more alive again. The government is not interested in this technology, since they fear it could endanger their position, and the scientist is forced to work together with a sinister organization. As you can probably guess, something goes wrong and before you know it a group of all-powerful superhumans roam the planet, intent on destroying everything and everybody, so that they can rebuild the planet from the ground up.
Enter Casshern, the son of the scientist responsible for these problems. He had died during the war, but his body came back to life in the same way the superhumans did. He gets a special super-armor in order to fight the superhumans and battle commences, especially when he discovers that the superhumans are for some reason holding his mother hostage.