 Superman rams a giant asteroid on a collision course with Earth. The impact causes the asteroid to now orbit the planet. However, Superman is staggered as he returns to Earth. He manages to change back to Clark Kent (apparently a reflex action) but doesn t remember who he is. Meanwhile, the orbiting asteroid still presents hazards for Earth. Only Superman can place an explosive device that will demolish the asteroid -- and no one, including Clark, knows where Superman is.