A child writes to the zoo asking for a pet. Each page has the shipping container, which open in various ways- and usually there is a bit of the animal peeking out. Lift the flaps and see what arrived- but most of them are of course unsuitable as pets- elephant, giraffe, lion, etc and get returned to the zoo. They keep diminishing in size down to a monkey, frog and finally a puppy which the child decides to keep. I think it's really cute and my toddler likes "opening" each package to find the animal inside. She loves puppies right now, so it has the perfect ending. My favorite page is the one featuring a lion- the flap of the crate actually has gaps cut so you see the lion's body through it- as pictured on the cover- and my kid always points out (delightedly) that his tongue is showing as the lion roars!