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.