Aqua is the original manga series by Kozue Amano, which serves as the precursor to the more well-known series Aria. Set on the terraformed planet Aqua (formerly Mars), it follows the daily lives of apprentice gondoliers in the city of Neo-Venezia. The story focuses on Akari Mizunashi as she trains to become an Undine, exploring themes of friendship and wonder in a serene, water-filled world.