After my first viewing I had an interpretation of the plot that was fairly straightforward. Two more viewings have only reinforced that interpretation.
(and before anyone accuses me of smug pretentiousness, Lynch has said that the film has a plot and I think my interpretation is the standard one. I do take some pride in having come up with it independently though 
)
Is it the one where one of the characters is a dream that the failed actress wishes she was?
If I had to say a plot, I would say that an actress arrives in L.A., meets an older actress, they get into a relationship and audition for the same movie and the older one becomes a success while the younger one fails. The older one then abandons the younger one who, in a fit of rage, orders the older one killed. But the older one survives and becomes amnesiac. The younger one commits suicide.
