I feel like an idiot for not getting the plot of the first movie.

The big theme is that, to be a courtesan, you play the game of harem politics and discard any attachments you have to climb to the top. Otherwise, you get crushed under the boot of your superiors until you get discarded yourself. The Mononoke is tellingly a Karakasa, a haunted umbrella that has been thrown away. The umbrella is also associated with courtesans and prostitutes, who use them to keep out of the sun and keep their skin white.

This I understand. What I don't get are the details of the actual story, and what the dynamic between the two girls was. Were they the same person, with one being the clumsy but personable personality they had to throw away? What was up with the brown girl and the guy at the bottom of the well at the end?