L'oiseau de feu (the ballet) centers on the
journey of its hero, Prince Ivan. Ivan enters the magical realm of
Kashchei the Immortal; all of the magical objects and creatures of
Kashchei are herein represented by a chromatic descending motif, usually
in the strings. While wandering in the gardens, he sees and chases the
Firebird. The Firebird, once caught by Ivan, begs for its life and
ultimately agrees to assist Ivan in exchange for eventual freedom.
Next, Prince Ivan sees thirteen princesses, with one of whom he falls
in love. The next day, Ivan chooses to confront Kashchei to ask to marry
one of the princesses; the two talk and eventually begin quarreling.
When Kashchei sends his magical creatures after Ivan, the Firebird, true
to its pledge, intervenes, bewitching the creatures and making them
dance an elaborate, energetic dance (the "Infernal Dance"). The
creatures and Kashchei then fall asleep; however, Kashchei awakens and
is then sent into another dance by the Firebird. While Kashchei is
bewitched, the Firebird tells Ivan the secret to Kashchei's immortality –
his soul is contained inside an enormous, magical egg. Ivan destroys
the egg, killing Kashchei. With Kashchei gone and his spell broken, the
magical creatures and the palace all disappear. All of the "real"
beings, including the princesses, awaken and with one final hint of the
Firebird's music, celebrate their victory. - From Wikipedia