Deformed since birth, a bitter man known only as The Phantom lives in the sewers underneath the Paris Opera House. He falls in love with the obscure chorus singer Christine, and privately tutors her while terrorizing the rest of the crew.

"Jellicle" cats join for a Jellicle ball where they rejoice with their leader, Old Deuteronomy. One cat will be chosen to go to the "Heavyside Layer" and be reborn.