Charlie is a guide-dog-puppy-in-training who goes to live with AJ and his family. Charlie struggles to stay focused. When she finally completes her training, she is unable to be placed with a suitable person. Instead, she goes back to live with AJ and becomes a therapy dog. The children are delighted as Charlie comes to school with them every day and helps out in the classroom and playground.
At the end of the story, children find out all about the work of therapy dogs in all sorts of situations, not just in schools.