"The Girl on the Dock" (the so-called James Potter 2.5) is an addition book to the series of books about James Potter, the son of Harry Potter. Returning to her grandfather's house after graduating from school, the young witch Petra Morganstern feels that she has changed. Confident in her last choice, but plagued by dreams of what it cost her, Petra doesn't know what to do with the rest of her life. The only ray of hope is her younger half-sister Isabella, whose simple-minded charm contrasts with the terrible Phyllis, her hated mother. Desperate to protect Isabella from Phyllis's growing wrath, Petra struggles to find a balance between the forces that seek to control her soul. Will she remain true to the choice she has already made, abandoning her own greatest desire in favor of good, or will the specter of power and vengeance that lives in the far corner of her mind destroy her completely? As everything spirals out of control, Petra is faced with the inexorable force of fate, once again pushing her to the last choice. Only this time no one will come to save you. This time Petra is forced to decide alone.