Nine-year-old Phineas William Walsh has an encyclopedic knowledge of the natural world. He knows that rockfish have swim bladders that can burst and push their intestines out their butts, and he knows that barnacles have the longest penises in the animal kingdom. Hes obsessed with animals; its practically all he talks about, and he spends all his spare time watching the Green Channel or researching obscure facts on the internet or in books. And hes worried sick about what humans are doing to the planet and its other animals.But although he seems to know absolutely everything about the animal world, what he doesnt know is why his granddad had to die or why Lyle the bully always picks on him or why his parents cant live together. He misses his grandad terribly, and he hates to see his grandmother the only person who understands his eco-worrying so sad. He misses his dad, too, and wishes he could see him more, and that the separation didnt make his mom so lonely though he sure doesnt like her talking to creepy Brent. And things only get worse when Phins mom, desperately worried about his animal obsession, takes him to see a rather unsympathetic psychologist. When his Grade 4 class gets a pet frog a Whites Tree Frog from Australia it becomes the perfect focus for all Phins worrying. He cant bear to see Cuddles penned up in a cage so very far from his natural habitat just for the amusement of humans. Its just another example of how cruel and self-centred humans are. And so Phin and his best pal, Bird, are spurred to action.