Synopsis

The following is a plot summary of Cats the musical. For more context, see the main article of each musical number. Note that this is a general synopsis and some of the plot details may vary depending on the production.

Act I – When Cats Are Maddened by the Midnight Dance
After the overture, the Jellicle cats gather on stage and celebrate the unique abilities of their tribe ("Jellicle Songs for Jellicle Cats"). The cats then notice that they are being watched by a human audience and proceed to explain how the different members of the tribe are named ("The Naming of Cats"). Slowly the cats disperse, leaving only a white kitten, Victoria, who performs a ballet solo symbolising her coming of age. She is soon joined by Mistoffelees, and together they invite everyone to the Jellicle Ball ("Invitation to the Jellicle Ball"). Munkustrap, the narrator, explains that tonight the tribe's patriarch Old Deuteronomy will make an appearance and choose one of the cats to be reborn into a new life on the Heaviside Layer.

As the Jellicles wonder who it will be, Munkustrap introduces a cat he has in mind: Jennyanydots ("The Old Gumbie Cat"). Jennyanydots is a large tabby cat who is lazy by day, but active by night as she keeps all the household pests in line. As her song comes to an end, the tribe gathers to welcome Jennyanydots, but are interrupted by the entrance of Rum Tum Tugger ("The Rum Tum Tugger"). He is very fickle and unappeasable, "for he will do as he do do, and there's no doing anything about it." The rockstar of the tribe, his number sends the kittens swooning and the adults groaning.

Then, as the cats are revelling in a reprise of Rum Tum Tugger's song, a shabby old grey cat stumbles out wanting to be reconciled; it is Grizabella. Most of the cats back away from her in fear and disgust as Demeter and Bombalurina explain her unfortunate state ("Grizabella: The Glamour Cat"). Grizabella is rejected and leaves; meanwhile, the gloomy mood is lifted as the music changes to a cheerful upbeat number, signalling the appearance of Bustopher Jones ("Bustopher Jones: The Cat About Town"). He is a fat cat in "a coat of fastidious black" who makes frequent visits to prestigious gentlemen's clubs. Suddenly, a loud crash startles the tribe and the cats run offstage in fright. Hushed giggling sounds mark the entrance of Mungojerrie and Rumpleteazer, a pair of near-identical cats ("Mungojerrie and Rumpleteazer"). They are mischievous burglars who enjoy causing trouble around their human neighbourhood.

The tribe confront Mungojerrie and Rumpleteazer, but are interrupted by the arrival of the Jellicle patriarch, Old Deuteronomy ("Old Deuteronomy"). He is a wise old cat who "has lived many lives" and is tasked with choosing which Jellicle will go to the Heaviside Layer every year. The cats put on a play for Old Deuteronomy, telling the story of the Great Rumpus Cat - a superhero-like figure who single-handedly scares away two warring dog tribes ("The Awefull Battle of the Pekes and the Pollicles"). A sombre moral from Old Deuteronomy is interrupted by a second loud crash, sending the alarmed cats scurrying. After a quick patrol for the villainous Macavity, Old Deuteronomy deems it a false alarm and summons the cats back ("The Song of the Jellicles"). The main celebration begins and the cats display their "Terpsichorean powers" ("The Jellicle Ball").

During the Ball, Grizabella reappears and is once again shunned by the tribe ("Grizabella: The Glamour Cat (Reprise)"). She tries to mimic the other cats' dance moves, but her age and decrepit condition prevent her from doing so ("Memory (Prelude)"). With Old Deuteronomy watching sadly from a distance, she reaches her hand out behind her, hoping another cat will touch and accept her. Rejected once again, she slinks off into the night.