Planet 46 is the 1st produced and 1st broadcast episode of British television series Fireball XL5.
A mysterious spacecraft sent from Planet 46 was sent to destroy earth. The crew of Fireball XL5 is ordered to investigate Planet 46, before another spacecraft is sent.
A spaceship called Fireball XL5, on board Steve Zodiac, Venus, Professor Matic and Robert the Robot, are told to intercept. They fire a missile but before it reaches the spacecraft, it explodes. They work out that there must be a crew aboard. They fire another missile while using a jamming beam.
They destroy the spacecraft. Then they are told that the spacecraft was launched from Planet 46, so Fireball XL5 goes on to investigate. Once they arrive, Steve and Venus head out in the front of Fireball XL5, while leaving the Professor and Robert back on the craft.
Once they arrive on the planet surface, they get out on their jet mobiles to investigate the surrounding areas. They find a cave and enter, where they find the door of a base. Without warning, aliens known as Subterrains, come in through rayproof tubes and shoot Steve with Coma Rays.
When Steve comes to, the alien leader tells him that they have put Venus on board a spacecraft; similar to the one they faced earlier. The leader says that they will release Venus, if Steve instructs the rest of Fireball XL5 to land in a certain position. Having no choice, Steve instructs the Professor land the Fireball XL5 at the position instructed.
When it lands they find that Fireball XL5 has landed in a quick-sand pit and cannot escape. This was a trap set up by the aliens. Steve then finds out that they will not release Venus and the spacecraft is launched. The aliens are distracted for a brief moment because of a malfunction on the spacecraft. This gives Steve the change to grab a gun while no one is watching him. After the aliens have fixed the malfunction, Steve knocks them all out with the gun.
He heads back to Fireball Junior, takes off, and connects back with Fireball, which allows it to fly out of the quicksand, They recover Venus and stop the alien spacecraft from destroying earth.
- This episode, like most of the first episodes of Supermarionation series, has no title.
- How did the Subterrain Commander know Steve's name?