Aired: Oct 6, 2015. A young girl idolizes the world-renowned S-ranked butei Kanzaki H. Aria and plans to follow in her footsteps; however, her test grades turn out as only an E-rank! All is not lost, however, as Aria agrees to give her some pointers. Can Aria help this newcomer become a first-rate butei?
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.
The story takes place in Tokyo Butei High School, a special school where armed detectives â€” "Butei" â€” are trained to use weapons. Kinji Tooyama is a second-year-student who has a special ability, but he keeps it a secret to maintain an ordinary, peaceful life. However, when he gets caught in a bombing on the way to school, he encounters H. Aria Kanzaki, the most powerful S-Rank Butei student in Assault Studies.
It is the year 2301. Man has terraformed Mars into a beautiful water planet, and has renamed it "Aqua". Built upon it is Neo-Venezia, an exact replica of old Venice, with beautiful waterways, palaces and plazas. Akari Mizunashi, a 15 year old girl arrives from Man-Home (formerly known as Earth) to become a gondolier trainee at a company called Aria Company. The company is lead by Alicia Florence, one of the three best gondoliers, also known as the three Water Fairies. Trough hard training, Akari aims to become a Prima herself. Many encounters and mysterious events are sure to follow on this planet of miracles.