In 1947, a French Canadian man named Emile Beaulieu throws his 12-year-old daughter, Evelyne (Evie) into a swimming pool, “hoping that she would sink to the bottom” (49). Emile is one of the men responsible for inventing the aqualung (an early example of Self-Contained Underwater Breathing Apparatus, or SCUBA equipment). He throws Evie into the pool, equipped with the aqualung, to show that the invention works. Evelyne develops a love of diving, which comes to define her life. She refines this love of diving and the ocean through the work of Jacques Cousteau, a colleague of her father.

Eighty years later, Evelyne is an old woman. She’s diving in the oceans around Makatea and is working on one final book about the ocean while trapped “in a failing body” (55). In the water, however, she feels alive. She explores the coral reefs and takes in bountiful life, including numerous gigantic but docile manta rays. She can recognize the individual rays and believes that they’re trying to socialize with her. The manta rays are a threatened species, and the people of islands like Makatea lack the resources to prevent illegal poaching. Evelyne hopes to tell the world about the intelligence and playfulness of the manta rays and other species, to halt the decimation of the environment.