This book as such a wild concept, and ENTIRELY new to me, for a kind of post-apocalyptic-universe type plot. First, I've read a lot of post-apocalyptic fiction, and for a new concept to be presented to me, well, good flippin' job! Second, this book is for younger audiences and it's definitely clearly for the younger set (in terms of writing style and plot development/resolution).

The plot of the book opens with, quite literally, an entire group of people (mixed ages) trapped on a football-field-sized jellyfish. This jellyfish delivers fish, usually daily, for food - no description about how they go about their freshwater consumption, but we can assume they just worked something out. They do somehow have a fire made from dried out driftwood and kept underneath a shelter made of plastic bags and other driftwood. But a large part of the overall enjoyment of this book is just accepting that you don't get all the backstory and inside information about how they got there, how they survive, how long it's been, etc. You just have to accept a good amount of the story, which I really didn't have trouble with because it's all so fascinating. The jellyfish doesn't let anyone go, going so far as to retrieve and place escapees back on the surface when they get to a certain distance. So there's quite a bit of plotting to get off and back to the distant shore they can see from their floating place on the water. They can see giant crustaceans they call "kriks" walking the shore sometimes, and it's alluded to that these things are violent and potentially the reason not many people are ever seen. They can go really fast and they have huge snappy crab claws. So that's really the whole thing, not a lot is happening, it's more about day to day happenings, planning to escape, planning what to do, interacting with various oddballs, etc.

The other big part of this book is environmental issues/global warming. We learn that sea levels have risen to the extent that shorelines totally changed, large sections of houses and roads are submerged. There are also so many plastic bottles and bags in the ocean that the people on the jellyfish have no problem building a structure for shelter, making clothes of plastic bags to protect from the elements, making sports balls from bottles and bags, etc. The message about plastic waste in our world's oceans is obvious.

And lastly, I'm so glad I read the acknowledgements by the author at the end, because I learned that this story began as a teaching tool made by a teacher to teach about environmental impact of plastic and global warming. The students then got into it and wanted more story, so the teacher embarked on a project to essentially write a book, with various input from students and friends. I love that, and it really makes the book even more enjoyable!