Like Transformers, the toys and cartoon don't quite have the same background
to start with.
Original (Toy) Premise: The evil Beast Planet scours the universe like
Unicron or Galactus, looking for worlds to feed on. It found one (planet
Aurora) too big to eat all at once, so it blasted it into bite-sized chunks.
The chunks are getting their acts together and fighting back, however. Rock,
Tek, Ice and Bone are the first War Planets to arise from the rubble, facing
down the Beast Planet and its lackey, Planet Remora. As the dust settles,
other War Planets will mobilize, as well as smaller moons and other forces on
both sides.
See the Fanfic Page for some expansion on this
background, as I see it. As should be obvious by now, the cartoon went in a
totally different direction, abandoning the whole Aurora idea.
Cartoon Premise: After destroying the cyborg-inhabited Planet Tek, the forces
of the Beast Planet come to a new starsystem, where four worlds live in an
uneasy symbiosis. Princess Tekla, the sole survivor of Tek, comes barely
ahead of the forces of the Beast, in a desperate bid to warn the new
targets. It falls upon a simple Miner from planet Rock named Graveheart to
create an alliance between the four worlds and fight off the Beast.