The set consists of countless pieces of to-scale rubbish, forming what is fondly known as the Jellicle Junkyard. All is quiet and still. A gold and black queen (female cat) creeps onto the stage. She is frightened by the noise and light of a passing car and so she darts into a pipe, glancing out. From the shadows somewhere slinks a grey tabby tom (male cat). Various cats appear from their hiding places as if by magic...they begin to sing "Jellicle Songs for Jellicle Cats", praising the glory of being a Jellicle.
At the end of this song the cats read the confusion in the audience members' faces, and Munkustrap--the grey tabby--presents the question: "What's a Jellicle cat?" The cats then begin chanting "The Naming of Cats", in which we learn that every cat has three different names: a name the cat's human family uses; a more unique name that his fellow cats address him by; and a secret name that the cat himself knows, and will never confess.
After this all the cats slink off stage except for a young white kitten named Victoria, who starts a beautiful solo dance in the moonlight. This is the "Invitation to the Jellicle Ball." The rest of the cats come back out, and Munkustrap explains that Jellicles meet once a year to rejoice at the Jellicle Ball, where their beloved leader, the wise Old Deuteronomy, names one cat worthy of journeying to the Heaviside Layer (sort of a cat heaven) and begin a different Jellicle life.
At this point each Jellicle takes a turn introducing him/herself, hoping to be the lucky cat chosen. First up is Jennyanydots, the Old Gumbie Cat. She does little during the day except sit...and sit...and sit...and sit some more. But at night, when her humans go to sleep, she is very busy teaching the mice to knit and getting employment for the thingyroaches and such.
After Jenny's song and dance number, a tall, furry, good-looking tom saunters onto the stage. This is the Rum Tum Tugger, and he is next to "audition." He is a very contrary cat--he'll never eat what you put in front of him, and he's always on the wrong side of every door! All the queens--ESPECIALLY the kittens--are infatuated with him.
At the end of Tugg's number, an old, haggard queen limps onto the stage. The Jellicles all shun her and hiss at her. The older cats pull the kittens away from her as they try to touch her. This is Grizabella, the Glamour Cat, who left the tribe long ago to seek a stage career. Now she wants to be accepted again, but the Jellicles feel she has betrayed them, and so shun her. The next Jellicle to "audition" is Bustopher Jones, the Cat About Town. He's a very well-to-do, very FAT cat who loves eating at four-star restaurants.
As Busto's number is ending, there is a flash of lightning. "Macavity!" cries the gold-coloured cat, Demeter, and all the Jellicles scatter. There is a pause, and then a high-pitched giggle is heard, followed by a loud "Shhh!" Two suspicious-looking striped cats appear with bags slung over their shoulders. These are Mungojerrie and Rumpelteazer, two mischief-making catburglars that love tormenting the family with whom they live. If anything turns up missing--you can be certain it was either Mungojerrie or Rumpelteazer...or BOTH! The other Jellicles come out at the end of their number and corner them, taking their bags of loot and throwing them out of the Junkyard.
Mistoffelees, a young black tom, turns away from the rest of the Jellicles, sensing something. "Old Deuteronomy?" Tantomile and Coricopat, the twins, follow up with: "I believe it is Old Deuteronomy!" Munkustrap and the Rum Tum Tugger tell us that Old Deuteronomy, the wise Jellicle leader, has lived nearly forever and has had many children. It is believed, in fact, that Old Deuteronomy is father to many of the Jellicles present at the Ball. And Old Deuteronomy appears, looking wise and fatherly. Now that he's here, the festivities can really begin.
Munkustrap starts a pageant that the Jellicles have prepared for their leader, entitled "Of the Awful Battle of the Pekes and the Pollicles: Together With Some Account of the Participation of the Pugs and the Poms, and the Intervention of the Great Rumpus Cat." This pageant tells of two rival groups of dogs who bark at each other all night long, and of how the Great Rumpus Cat scared them into stopping. After this Old Deuteronomy reminds the Jellicles that both cats and dogs are equal in their mortality.
There is another lightning flash, and thunder is heard. "Macavity!" cries Demeter, and again all the Jellicles scatter. Only Old Deuteronomy and Munkustrap remain. When they are convinced that there is no danger, Old Deuteronomy calls out the Invitation to the Jellicle Ball again. The cats slink back onto stage as the Jellicle Ball truly begins, telling us what makes a Jellicle cat; what Jellicles do and how they look. (Of course, it is revealed in an unpublished poem of Eliot's that all cats are really Jellicle cats, and all dogs are really Pollicle dogs.)
After a vigorous dance--and after a brief catnap, during which the white kitten, Victoria, becomes an adult--Grizabella slinks onto the stage again. The Jellicles, hissing and turning away from her, leave the stage--all but Old Deuteronomy, who remains without Grizabella realising it. Supposing herself to be alone, Grizabella sings the beautiful, heartwarming "Memory," in which she reveals her overwhelming desire to be accepted and loved by the Jellicles once more. As she limps sadly off the stage, Old Deuteronomy wants to touch her but decides that it is not yet the right time.
Grizabella exits, and the rest of the Jellicles re-enter. Old Deuteronomy sings "The Moments of Happiness," and the youngest kitten, Jemima, sings a touching small bit of "Memory." Then the "auditions" resume.
Next up is Gus, the Theatre Cat, who is an old veteran of the theatre. He sings of his younger days, when he starred in such brilliant roles as "Firefrorefiddle, the Fiend of the Fell" and "Growltiger." He is confident that his acting skills have not left him, and he demonstrates by again taking on the role of Growltiger in "Growltiger's Last Stand." This tells of a pirate cat who was forced, by the group of animals he'd tormented, to walk the plank.
After Gus is Skimbleshanks, the Railway Cat, who rides along on the Midnight Mail, seeing that the passengers are comfortable and making sure that nothing goes wrong. Skimble sees that there's no nonsense and that everything runs smoothly!
At the end of Skimble's song there is yet another crash of thunder and flash of lightning, and a fire-striped cat appears, laughing wickedly. This is the infamous Macavity! He, accompanied by several black rats (or are they henchcats? there are debates), throw a net over Old Deuteronomy and take him away. The Jellicles, terrified at the loss of their leader, all scatter, except for Demeter and her sister--a red queen called Bombalurina. The two queens sing about Macavity, the Mystery Cat, who's responsible for many unspeakeable crimes but is nowhere to be found when they are committed.
The Jellicles reappear during the number, and at the end of it the black rats (henchcats?) bring Old Deuteronomy back...or so it seems. All the cats run to embrace their leader--all but Demeter, who hisses warningly and then attacks him. The reason for this soon becomes clear as the Old Deuteronomy disguise falls away revealing--Macavity! Munkustrap and the other Jellicles fight Macavity until at last, tired and almost beaten, he disappears--but not before destroying the Jellicles' source of light.
"We have to find Old Deuteronomy!" the cats sing mournfully, and the Rum Tum Tugger replies from a junkpile, "You ought to ask Mr. Mistoffelees." Magical Mr. Mistoffelees is the Original Conjuring Cat, a small black tom with mysterious powers. He restores light to the Yard, and after showing off many of his spectacular tricks, he conjurs back Old Deuteronomy.
Now that their leader has been safely returned to them, Munkustrap says it is time for Old Deuteronomy to make "...the Jellicle choice...announce the cat who can now be reborn..."
As the hopeful Jellicles reach out their paws to Old Deuteronomy, who should limp out onto the stage but Grizabella! The cats do not leave her alone this time, instead they all go to various parts of the Yard and turn their backs on her--except for Old Deuteronomy, who raises a paw, wanting to hear what she has to say. Grizabella then sings "Memory" again, this time for all the Jellicles to hear, and one by one they turn to face her. She implores the Jellicles to touch her, to accept her, to "...understand what happiness is..."
As Grizabella finishes and starts off the stage, she reaches a paw out behind her hopefully. And it is Victoria, the young white cat, who is the first to touch and accept her. One by one, all the Jellicles do the same--and when she reaches Old Deuteronomy, he bows to her. The reason? She has been chosen to go to the Heaviside Layer. The Jellicles then beigin "The Journey to the Heaviside Layer," singing Grizabella to cat heaven and her new life.
This done, they gather around Old Deuteronomy as he sums everything up in "The Ad-dressing of Cats." He points out to the audience that "...cats are very much like you." And so the Jellicle Ball ends, and the cats disappear quietly back into the night from whence they came.