A five-mile-wide asteroid is heading straight for Metropolis! Superman is able to fly up and push it into a stable orbit, but the strain and the tumble back to Earth give him amnesia, and he forgets his identity — both of them. Meanwhile the orbiting asteroid is messing with our planet's tides. Clark finds the Superman costume and eventually concludes that he must be Superman, leading to a last-ditch attempt to save Earth.
This episode contains examples of:
- Artistic License Astronomy: Pretty remarkable even for a kids' show from the '50s.
- In this universe, asteroids take a meandering path through the solar system that scientists have no way to predict, even if they've been tracking its movements for some distance.
- Jimmy mentions that the asteroid flames up when it passes near a planet, and has already done so when it passed Mercury and Venus. Asteroids do flame up near planets ... when they're caught in the planet's gravitational pull and are burning up in the atmosphere. The show treats this as something that just happens without diverting or damaging the asteroid at all. Weirdly, when Superman eventually lands on the asteroid's surface there's no sign that it's in flames.
- Superman's cape flaps in the vacuum of space.
- Clothes Make the Superman: Amnesiac Clark theorizes that this is how the superpower thing works. Jimmy says, unfortunately, no, the man makes the clothes super.
- Deus ex Nukina: Naturally, the solution to the asteroid problem is for Superman to plant an atomic bomb on it.
- Easy Amnesia /Laser-Guided Amnesia: Superman forgets who he is, as well as who his friends are, but somehow remembers to change back into his Clark clothes when he lands. He also finds his way back to his apartment. After delivering the bomb he recovers his memory completely, with the explosion perhaps functioning as a Tap on the Head.
- Explosions in Space: The asteroid explosion looks pretty much like an earthly one.