In the 24th century on the planet Aqua, three girls—Akari Mizunashi, Alice Carroll, and Aika S. Granzchesta—continue to strive toward their goal of becoming Prima Undines: professional tour guide gondoliers. Fortunately, the girls receive guidance from the three top Prima Undines in Neo-Venezia—Alicia Florence, Athena Glory, and Akira E. Ferrari—who are known as the "Water Fairies" in recognition of their skill. With their assistance, the young apprentices train diligently and work to overcome any situations they encounter. As these three young girls experience both the joys and hardships of life, they do their best to improve as tour gondoliers in Neo-Venezia, a terraformed replica of Venice.