As a young girl, Nanami Simpson loses her mother and is taken in by her father, Scott Simpson, who works as a marine biologist aboard the Peperonchino research vessel. Scott's mission is to locate the Glowing Whale, but upon discovering the remains of one, he makes the decision to shift his focus to preserving and caring for all marine creatures. Nanami develops a close bond with an Orca she dubs Tico, and they swim together daily. Her newfound ability to breathe underwater impresses her father, but a close call nearly results in her drowning until a Glowing Whale miraculously saves her life and is finally observed by Scott.