On the planet Aqua lies the watery city of Neo Venezia, a tourist hub in which people travel around in gondolas. Professional gondoliers known as Undines are well-revered as they act as tour guides for the people. Akari Mizunashi is a gondolier in training and also an employee of Aria Company. She gets to meet all sorts of people as she takes them on the gondola rides, from friendly mentors to special individuals, all this admidst the beautiful scenic backdrop of the entire city.