The characters in The Court of Stone Children are of several generations, some of whom come from the past to influence events in the present. Several young adults are major characters, with Nina the most important. Also significant are Gil, a boy of this century, and Domi, a spirit-girl from the past.

Several adults are also important, but they assist, rather than lead, the younger characters' search for answers to the novel's puzzles.

Although Nina likes solitude, she also needs friends. She feels unhappy and insecure in her new home and in her school relationships, but has determined to improve her life. Nina loves old things (her "museum feeling," as she expresses it). The past represents a kind of security for her. She is drawn to Gil at least partly because he seems secure within himself. And although Nina is very bright, she realizes...