comment on structure

The novel is divided into 48 chapters, named simply "Chapter 1," "Chapter 2," and so on. The chapters are almost always short, but occasionally one will be ten pages or longer. The novel follows a mostly linear progression, following main character Iris through her life, with the occasional very brief chapter that is from Blue 55's perspective that detail significant events in his life. The main plot line involves Iris learning about Blue 55 and setting out to find him and play a song for him that he can hear since his call is at a frequency that renders it inaudible to other whales.