The musical tells the story of Elisabeth ("Sissi"), the Empress of Austria, from her engagement and marriage in 1854 to her murder in 1898 at the hands of the Italian anarchist Luigi Lucheni, through the lens of her growing obsession with Death as her marriage and her empire crumble around her at the turn of the century.

The plot adheres closely to the original novel, revolves around wealthy Maxim DeWinter, his naïve new wife, and Mrs. Danvers, the manipulative housekeeper of DeWinter's Cornish estate Manderley. Mrs. Danvers resents the new wife's intrusion and persuades the new wife that she is an unworthy replacement for the first Mrs. DeWinter, the glamorous and mysterious Rebecca, who perished in a drowning accident. The new Mrs. DeWinter struggles to find her identity and take control of her life among the shadows left by Rebecca.