It's a gala like no other: A wealthy philanthropist has brought the best scientific minds and deep-pocketed donors to her underwater mansion for a summit on one of Earth's most pressing crises: a deadly epidemic sweeping through the ancient aquean people, who have lived underseas for longer than humans have existed. And veteran reporter Hiroe Anno is determined to capture the story for her news service-even if it means overcoming her intense phobia of the ocean.

Then, guests start disappearing, and a young aquean poet pulls Hiroe-and her estranged mentor from a rival news service-into an investigation where each new disturbing discovery seems to raise new questions-about their hostess, about the nature of the disease, and about the search for the cure.