The bear has lost his hat and he asks everyone they meet if they haven't seen it. But no-one has.
Although some animals may answer more truthfully than other.
Until the stag asks what the hat looked like and then the bear remembers that he DID see his hat.
If you want your picture books nice and fluffy and bright, then this is not for you. If you can deal with or love a bit of black humour, then by all means get "I Want My Hat Back" by Jon Klassen. It's great for reading aloud, especially if you do the voices and of course you must do the voices.
I like the art a lot, it's simple but very expressive. I have this thing for characters who mainly communicate their emotions with their eyes and Klassen does this extremely well. He's also great at telling a story with very few or no word at all.