Le monde des musicals

Acte I
When Cats Are Maddened by the Midnight Dance
After the overture, the Cats gather on stage and explain the Jellicle tribe and their purpose (Jellicle Songs for Jellicle Cats). The Cats (who constantly break the fourth wall, in the musical) spot the human audience and explain how the different Cats of the tribe are named (The Naming of Cats). This is followed by a dance from Victoria the White Cat that signals the beginning of the Jellicle Ball (The Invitation To The Jellicle Ball) and Munkustrap tells us that tonight is the night when Old Deuteronomy will choose a cat to be reborn into a new life on the Heaviside Layer.
Munkustrap appears and introduces Jennyanydots (The Old Gumbie Cat), a large tabby cat. She "sits and sits and sits" all day, while at night she rules over the mice and cockroaches, teaching various activities to them. Jennyanydots finishes, greets the other cats, but is interrupted. The music instantly changes, and The Rum Tum Tugger makes an extravagant entrance (The Rum Tum Tugger). The Tugger is a Tom with a wild mane and leopard spots on his chest. He is very fickle and unappeasable, "for he will do as he do do and there's no doing anything about it".
A shabby old grey cat stumbles out and looks around. It is Grizabella. All the cats back away. The cats sing of her saddened, unfortunate state (Grizabella: The Glamour Cat). Grizabella leaves and the music changes to a cheerful upbeat. Bustopher Jones, a fat cat in "a coat of fastidious black", appears (Bustopher Jones: The Cat About Town). Bustopher Jones is among the elite of the cats, and visits prestigious gentleman's clubs. A loud crash startles the tribe. Could this be Macavity? The cats run off the stage in fright. Hushed giggling signals the entrance of Mungojerrie and Rumpelteazer, a pair of near-identical cats. They are petty burglars, very mischievous, and they enjoy causing trouble for human families (Mungojerrie and Rumpelteazer).
Finally, the Jellicle patriarch, Old Deuteronomy, shows up (Old Deuteronomy). He is a large old Cat that "has lived many lives" and "married nine wives (And more, I am tempted to say – ninety-nine)". He is the one who will choose which Jellicle cat will go to the Heaviside Layer. In most productions, at this point, the cats perform a song (The Awful Battle of the Pekes and the Pollicles) for Old Deuteronomy. It is a story about two dog tribes clashing in the street and subsequently being scared away by the Great Rumpus Cat, a cat with flashing red eyes. After a few words from Old Deuteronomy on the destiny of Jellicle Cats and Pollicle Dogs, a second loud crash, presumably from Macavity, sends the alarmed cats scurrying. But Old Deuteronomy calls them back and the main celebration begins (The Jellicle Ball), in which the cats sing, dance and display their "terpsichorean powers".
After the Ball, Grizabella reappears and tries to dance, but her age and decrepit condition prevent her from doing so. Once again, she is shunned by the other cats, but that does not stop her from singing a short version of Memory.

Acte II
Why Will the Summer Day Delay — When Will Time Flow Away?
After the Jellicle Ball, Old Deuteronomy sings of "what happiness is", referring to Grizabella. This message naturally goes over everyone's heads, so he sends the message again and Jemima (or Sillabub, depending on the production) sings it for everyone to hear, (The Moments of Happiness). Gus — short for Asparagus — shuffles forward ('Gus: The Theatre Cat'). He is the cat that once was a famous actor but now he is old and "suffers from palsy which makes his paws shake". He is accompanied by Jellylorum, who tells of his exploits. Gus then remembers how he once played the infamous Growltiger, Terror of the Thames (Growltiger's Last Stand). He tells the story about the pirate's romance with Griddlebone and how he was overtaken by the Siamese and forced to walk the plank.
Back in the present, after Gus exits, Skimbleshanks is sleeping in the corner (Skimbleshanks: The Railway Cat), a cat who is unofficially in charge of the night train to Glasgow. He is very clever and very important because if he is gone "the train can’t start". Within his song, a whole locomotive train engine is assembled out of objects in the junkyard, with various cats spinning wheels, holding up the structure and lighting the headlights.
With a third crash and an evil laugh, the "most wanted" cat, Macavity appears. He is a "master criminal" and never is found at the scene of the crime. He is a horrifying looking cat and a "villain" of the Jellicle Tribe. Macavity's minions throw a net over Old Deuteronomy and capture him. As the other cats try to follow him, Demeter and Bombalurina sing what they know about Macavity, as they have had some sort of past with him (Macavity: The Mystery Cat). When they are finished, Macavity returns disguised as Old Deuteronomy. When revealed by Demeter, he fights with Munkustrap and Alonzo. Though he holds his own for a time, Macavity is overwhelmed by the two younger tomcats; as the rest of the tribe begins to gang up and surround him, he shorts out the stage lights and escapes in the confusion.
Rum Tum Tugger suggests that the cats find Mr. Mistoffelees (Magical Mr. Mistoffelees). Mr. Mistoffelees is black and small and can perform many feats of magic that no other cat can do. Mr. Mistoffelees performs his dance, which is often one of the most intricate and challenging dance solos in the show. The magical cat restores the lights and brings back Old Deuteronomy, earning praise from all the cats. The Jellicle choice can now be made.
Old Deuteronomy sits down and Grizabella appears for the final time. Old Deuteronomy allows her to have a chance to address the cats. Her faded appearance and lonely disposition have little effect on her song (Memory). With encouragement from Jemima and Victoria accepting her always, the appeal succeeds and she is chosen to be the one to go to the Heavyside Layer and be reborn to a new Jellicle Life. (Journey to the Heaviside Layer). A large tire rises up with Old Deuteronomy and Grizabella. Once at the top Grizabella finishes the journey herself. Old Deuteronomy gives his closing speech to the human audience (The Ad-dressing of Cats) and the show comes to a close.