Elisabeth tells the story of the last Austrian Empress, Elisabeth. The story is a flashback, not unlike what we see in Evita, with the character of Elisabeth aging from 14 to 61. We see her innocence, how she was manipulated by her mother-in-law, her liberation, her obsession with beauty, and (what the musical revolves around) her love affair with death. I won't go into the details of the show, as I think Stacy's Musical Village does a wonderful job with a synopsis of Elisabeth at http://www.theatre-musical.com/elisabeth.html. She has included the entire libretto (with some translations), pictures, and a host of other information in English.
With gorgeous music by Sylvester Levay and words by Michael Kunze, this is one musical that will not disappoint, even on CD. The musical style varies greatly throughout the show, from an organ fugue, pop musical, rock, and even a touch of opera, it's a bit like Evita meets Phantom of the Opera.
One difficulty with this show is that the recordings are not widely available in the United States. I obtained some from Musical-Shop.de, but they are also available from websites like Sound of Music (based in Germany) and even Amazon.com (where I happened to score the 2CD Vienna recording for $6).
Don't ignore this musical because you don't know German (or Dutch, or Japanese, depending upon the recording you find). Even if you can't understand much, this music is so beautiful that you'll be missing something wonderful if you don't listen to it.
A few audio clips:
Original Vienna cast: Milch: Company
Original Vienna Cast: Ich Gehore Nur Mir: Pia Douwes
1995 Vienna Cast: All Fragen Sind Gestellt: Company
Essen: Wenn Ich Tanzen Will: Pia Douwes and Uwe Kroeger
Netherlands: Niets, Niets, Echt Niets: Pia Douwes
If you want to learn more about the actual life of Empress Elisabeth, I'd suggest reading Brigitte Hamann's The Reluctant Empress which provides a detailed biography of her life.
For discussion of the musical, there is the Sisi - Elisabeth mailing list at http://groups.yahoo.com/group/sisi/ or Elisabeththemusical at http://uk.groups.yahoo.com/group/elisabeththemusical/.