That was how the late Carl Sagan would describe how many stars there are in the cosmos. And that’s how many ideas there are out there for books and stories. Some are even good. That’s not to say the rest are not, no. It’s just that they never get exposure (like undiscovered planets) and therefore are unfairly consigned to the scrap heap or a desk drawer unfinished.
However, all of those stories fall into one of seven tropes or plots. In no particular order, they are: the quest; a voyage and return; rebirth; tragedy; rags to riches; comedy; and overcoming the monster. Any story may be a hybrid of these, but this about covers the basic plots.
A question I’ve been asked is have I chosen a particular plot before writing a story. No, consciously I haven’t but that doesn’t mean other writers follow the same game plan. There’s more of them (billions and billions) than the seven tropes listed above.
But, it could be lurking in my subsconscious as the idea develops. To paraphrase an old-time radio show, The Shadow, “Who knows what lurks in the mind of the writer?” At the outset, I sure as hell don’t. That’s to be discovered in the writing. It will go where it wants to.
Do I know how the story will end? No, just like life, I don’t. It’s not circular, ending where we started. It’s one of the tropes mentioned earlier, the quest, just one of billions, yet to be revealed.