A family of Bottles comes to a city full of people and crushable cans to set up shop and reveal the extraordinary wonder of bottles to humans, but the Bottle family finds itself snubbed until a flood threatens the city and only the Bottles can save it.
Let's state first and foremost that the illustrations in this book are really very nice. They can make you believe in walking, talking bottles... including a baby with a bottle nipple for a hat and a cat who can't curl up.
But the story... I don't think it holds together that well. It's one of those "picked on person/group of people has a special talent that saves the day!" stories. As a general rule, I'm not a fan of those. The message always seems to be intended to be "everybody has a special gift" or "don't snub your neighbors", but it usually - as in this book - comes out sounding like "it's okay to dislike somebody for what they are because if you make nice-nice to them when you NEED them, they'll help you anyway". And that's... that's not really a very nice message at all. Though it might be the truth.
This is made worse by the fact that the Bottles (who come from a land of bottles... where, we can only hope, they actually do have more than one last name) moved to this human city specifically to evangelicize about how great bottles are. (Interestingly, the neighbors specifically snub them for acting like bottles, not for *being* bottles - presumably, if they'd had any intent to conform they would've been fine.) Well, no matter how nice somebody is, I don't much like being preached to either... and really, how can this be translated to real life? That weird kid you made fun of in school wasn't there to show you he was better than you, he was there because he had to be there, whether he was better than you or not!
Anyway, there's a typically contrived ending wherein the dam breaks and bottles are needed to hold up all the water, so the Bottles do that and save the day and everybody is friends and then the cat curls up yay. Saw that coming.
It's not the worst book of this style that I've read, but really, you can do better. If you want a book about not fitting in (but being valued anyway) try Tacky the Penguin.