The story begins with the ever-dreaded phone call in the middle of the night, summoning Kitty to London because something's happened to her mother. Heavily pregnant herself, Kitty gets on the first flight, and, we think, starts the story from the beginning to demonstrate how she and her family got to the point where her mother lies in the hospital.
As a child, Kitty lived a somewhat idyllic life in the English countryside with her mother, brother, sister, aunts, grandparents, and nanny. Dahl vividly describes her setting, and one can almost feel the warmth of the sun and the breeze.
But Kitty is not destined to remain there. Kitty's mother, Marina, is presented to the reader as someone who does not make the best choices in life. Kitty herself is the product of an affair Marina had as a teenager with a married man. As the story begins, Marina has just found religion, through Swami-ji, the leader of an unnamed cult.
Though benevolent in intention, the effect of the cult on Kitty's family is dramatic. Soon, Kitty is separated from her family and sent to a drab boarding school, while her mother and siblings go to New York. Her mother becomes a successful painter in New York, and after a single school year, decides that Kitty should join her. She does, and it is in New York that Kitty first begins to follow her mother's example in walking on the wild side.
When the family moves back to London (having been rejected by the cult), Kitty's inhibitions seem to stay in New York. Once in London, she falls in with varying crowds, doing drugs, going to wild parties, and the like. From the loose time references we are given in the book, it is the mid-'90s and Kitty is about 14. Not to be overly naive, but she is far too young to be doing the sorts of things she does (I guess that's where the book gets its title), but even worse is that Marina encourages Kitty's behavior, sometimes even joining her at parties, and passing around the drugs. That Marina genuinely loves Kitty makes this picture even more tragic, as it does not ever seem to occur to Marina that her choices and behavior might be destructive to her children. Finally, Marina takes an overdose and is rushed to the hospital. Kitty calls her grandparents, and is finally able to return to their home.
But, although the scene has remained the same, Kitty herself has changed too much to stay there, and decides to go back to boarding school, this time in Connecticut, to make a new start. But here is where the book fails us. Having detailed Kitty's descent, Dahl leaves her redemption to our imagination. We know only that she does manage to make a stable life for herself. Having spent so much time in the dregs with Kitty, it would have been nice if we could have walked with her a bit on her journey up.