The spirit world merges and clashes with the real world at a gravesite in the dark of night.

St. Petersburg Ballet Theatre, an international touring Russian ballet company, performs "Giselle" in its debut Sunday at Governors State University's Center for Performing Arts.

The exclusive Chicago area engagement is part of a U.S. tour that runs through early May.

First performed in Paris in 1841, "Giselle" tells the tale of a peasant girl and her all-consuming but ill-fated love for a prince (who doesn't reveal his true identity to her), and the redeeming power of her love.

The music was composed by Adolphe Adam, best known for the Christmas carol "O Holy Night."

Artistic director Yuri Petukhov characterizes the music as "beautiful, romantic and dramatic."

The first act takes place in a Rhineland village just before its joyous wine festival. Albert, a prince in peasant disguise, falls in love with the peasant girl Giselle but keeps his title a secret from her. He also doesn't tell her he is already engaged to Batilda, daughter of the Duke.

When Giselle discovers the deceit, she despairs and dies of a broken heart.

The second act opens near midnight in a deserted churchyard, where Albert visits Giselle's grave and encounters the Wilis, ghosts of betrothed girls who, like Giselle, were betrayed by their lovers and died before their wedding days.

Roaming the forest at night seeking revenge on any man they meet, they force Albert to dance himself to death. But Giselle, now a Wili herself, intervenes to forgive and save him.

The dancing requires dramatic action as well as technique, Petukhov says, and it's important the dancers differentiate the realism of the first act from the fantasy of the second.

In addition to "Giselle," the company's current touring repertoire includes "Carmen," "Swan Lake," "Romeo and Juliet" and "Russian Seasons" (three one-acts).