Dear WW: Here is a link to synopsis of Opera version of Mourning Becomes Electra. It is short
enough you could read in in a few minutes. However, the plot sounds like a bunch of garbage
to me. A bunch of murders that just don't make sense, with daughter who is party to murder
of her mother shutting herself up in shuttered home, "the family tomb". My interpretation of
the title is now "The Bitch deserves to suffer".

http://www.mourningbecomeselectra.com/info.htm