When Luca first arrives at the dog park, the other dogs turn him away. "You're not a dog," they say, "You're a fox." But . . . Luca likes to chase cats. He likes to yip at mailmen. And he likes sniff other dogs you-know-where. Still, Luca has to admit, he doesn't look like the other dogs. So . . . he must be a fox, right? But when Luca finds a trio of foxes in the forest and asks to join them, they don't think that Luca is a fox at all. After all,...