Here, the only tokens are rise and fall and they must alternate. So you can enumerate plots by picking a starting token and a number of alternations. Thus there are Aleph_0 plots.
If you tracked multiple hero/protagonists then their interleavings could be uncountable.
Is it required that “rise” and “fall” be boolean/digital operations? I think it would be more reasonable to characterize them as analog/continuous. That could then lead to infinite variations in rates, even just with a single character. And that’s before considering whether the characters and reader are correct in determining their current trajectory—much as in real life.
If you tracked multiple hero/protagonists then their interleavings could be uncountable.