How Many Stories Are There, Really?

I have heard that there are only two possible stories in literature:

1. A stranger comes to town.
2. Someone goes on a journey.

The Child and I have spent a few lazy hours (in combination, not all at once) trying to apply this formula to everything we have read recently. For the most part it works (go ahead, take a minute and try it).

This website posits other possible plot formations in literature, breaking down one, three, seven, 20 and 36 possible plots in all of literature.

I am of the mind that whatever makes complex literature easier to understand initially will help students be more engaged and want to do the deeper work of understanding character and structure. I favor the "two plot" rule (and the 20-plot rule looks more like the elements of a quest to me).

Thoughts?