Bennington Austin "Bink" Cotwell IV, the infant son of socialites Laraine and Bennington Austin "Bing" Cotwell III, lives in a huge mansion in a suburb of Chicago and is just about to appear in the social pages of the newspaper. Three klutzy criminals, Edgar "Eddie" Mauser, Norbert "Norby" LeBlaw, and Victor "Veeko" Riley, disguise themselves as baby photographers from the newspaper and kidnap him, demanding a $5 million ransom. After the kidnapping, however, the criminals have difficulty controlling Bink at their apartment. Norby attempts to put him to sleep by reading his favorite storybook, "Baby's Day Out" (or "Boo-boo", as he calls it), only to fall asleep himself from boredom, leaving Bink unattended. Looking through the book, Bink notices a bird on the page and then one by the window; he follows it out and successfully gets away from his kidnappers. The ensuing chase culminates in Eddie falling off the building and into a garbage bin. Norby and Veeko rescue him and they begin pursuing Bink across the city.