Eight-year-old Emma McGraw is an only child who lives with her mom in their cozy condo. When four-year-old Anthony Scarpetto moves in for a week while his parents are away, Emma is not happy. He's loud, he smells, and he touches her stuff. And that's only half of it! Emma has started at a new school, and has finally begun to make friends. But how can she invite anyone over when annoying Anthony is there? Emma is in for a surprise, though. As the week goes by, she starts to realize that having a little brother may not be as bad as she thought.