The premise is simple.

I tell a story,
But you shape it.

You look, now, to the early days of Homestuck and say “Oh.” “Right, that.”
I look to it and say “Oh, yes, how things could have changed.”

Sure, the author may have had a general aim, but really? Not as fine a point as this all has accumulated to.

So, I myself will tell you the entire plot right now- Again state it:

I tell a story.

You shape it.

Nothing is as it seems, nothing is constant and nothing, nothing is going to end as you expect it to. This is not the same world that you are used to reading of, no. Not even the same galaxy or universe. Nay, this is its own reality, neatly removed from all else. As much as an entire reality can be removed from anything.