Oliver is thrilled that his mother is expecting a baby and convinced that his new sibling will be the brother of his dreams. Imagine his shock and disappointment when a little sister shows up instead! Oliver is determined to do what it takes to find a boy baby--even if that means trading in his sister-- but when his hilarious efforts are unsuccessful, he comes to realize that no one can take the place of his family's lovable new addition...even if she's a girl.