Imagine walking in the woods one spring day and finding an underground city Amazingly, Carillon Couperin does just that. This underground city is named Possum, from a Latin word, and Possum is a haven for people to collaborate on very exciting, even lifesaving projects. Possum's current project is top secret, and it involves Carillon's family and the recent injustices that have befallen them. Carillon gets involved in the work at Possum to solve the complex mystery that is at the heart of her family's problems. In the process, she learns to confront the bullies who ridicule her at school. And, with help from her brother, Matt, Carillon actually thwarts the plans of an evil tyrant who has already harmed her family tremendously and plans to do more. Possum is a magical place for Carillon. It is the most beautiful place she has ever seen, from its green marble hallways to the wonderful murals on the walls to the surrounding music. With each visit to this fantastic place, Carillon finds new possibilities and opportunities. She meets experts in various areas of learning, including technology, science, business, history, literature, music and art, and she finds guidance for her future life's work. Carillon also encounters adorable animals that are able to do astonishing things. Extraordinary people aid Carillon in her endeavors. Computer wizards and security experts are working at Possum to help her. Medical specialists are engaged in research to save lives of people around Carillon. As a very gifted musician herself, Carillon enjoys the talented musicians, artists, and writers that bring joy and beauty to Possum. To her happy surprise, Carillon discovers that some people are not what they seem at all. Is it possible that, after a dreadful year, Carillon Couperin's dreams are finally coming true?