First, establish the CATS people first... Are they human at first? Are they Jellicles? Are they something in-between?
Second, where are they - a distant planet or here on Earth?
Third, where is the Stargate?
Fourth, What happens to start the story...???
Again - to be an author, YOU are the one who must have an idea how your story starts. You have to have an idea, a draem, a thought, or some piece of imagination; or don't bother trying to write or tell a story - that is what an author does. You have to be able to start the story and end it (to a certain extent) - even a series has endings.
Using the three points above, I can think up at least four scenarios. A friend of mine can probably double or treble that... This is what has to be done, and YOU have to do it...
