Mary Margaret thinks her life would be perfect if only she had a pet. She's tried to convince her parents that she can handle the responsibility, but her mother is too busy worrying about having a baby, and her father is allergic to dander. The irrepressible eight-year-old concocts all sorts of crazy schemes (including selling handmade "poop purses" to neighborhood dog walkers) and suffers many mishaps on the way to becoming big enough inside to earn something warm and fuzzy to love. Mary Margaret's effervescent personality will make her popular with fans of Junie B. Jones, Ramona, and Amber Brown.