Harper is excited at the idea of being a big sister, but she becomes frustrated when the baby boy her parents adopt proves to be a lot of work, and her parents never seem to have time for her.

"When a young girl and her mother move to an apartment in a new city, the girl feels fine on her own. She would rather play by herself than meet new kids at the park or have a playdate with the other children in her building. And when her mom takes her to story time at the bookstore, she breaks down in tears. But things start to change when she meets Millie, a rescue dog who is not too big, not too small. On their daily walks, Millie isn't afraid...