All the cats in CATS are like one big family. They were all brought up in the same tribe, and love each other. Each year all the cats gather for the annual Jellicle Ball when one cat gets to go up to the magical Heaviside Layer and then comes back down to start a new life.
This year happend to be when old Grizabella the "Glamour Cat" decides to come back to her tribe.
When she was in the tribe she was very popular and all the cats loved her, but when she left to discover the outside "human" world they took that as though she was abandoning them. Years past and lots of times passing by where Grizabella was living (unfortunately around prostitues and such), the Jellicles could see how she was living and with whom she was hanging around. Poor Griz didn't mean to live where she was. Then when she came to them the first time the night of the Jellicle ball that year all tatterd and worn out, none of them except Victoria and Jemima were willing to accept her back.
As the night wore on lots of things happened. Old Dueteronomy the Jellicle leader, who is loved very much by the Jellicles, and who also loves Grizabella appeared and came to rejoice with them before makeing his decision.
Also that naughty cat whose wicked deeds are widely known, Macavity came to ruin their Jellicle Ball by kidnapping Old Dueteronomy just for fun!
Luckily Magical Mr. Mistoffelees, the world's most conjuring cat, saved the day by using his magical powers to find Old Dueteronomy.
Now Grizabella appears for the third time and tries to tell them how much she misses them and wants to be back in the tribe. This time Jemima sings "Memory with her and the other Jellicles begin to understand that she is not bad at heart and how terrible they were to her. They forgive her (with a touch of the hand) and not only do they forgive her and love her, but they send her up to the Heaviside layer to start a new life!
Then Old Dueteronomy sings about how Anyone should address a cat ("the Adressing of Cats") and the Jellicles realize their purpose in life and that cats are really a lot like you and me.
