A very large cat who has powers in black magic. He has been the head of the cat kingdom in Aqua for at least 100 years and is implied as the spiritual guardian of Aqua.  (Source: Wikipedia)

On the planet Aqua, a world once known as Mars, Akari Mizunashi has just made her home in the town of Neo-Venezia, a futuristic imitation of the ancient city of Venice. In pursuit of her dream to become an Undine — a gondolier who leads high-end tours around the city — Akari joins as a trainee with the Aria Company, one of the three most prestigious water-guide companies in Neo-Venezia. There, she explores the beauty of the city and the world along with other trainees from Aria and rival companies, working hard for her dreams and making new friends along the way.
 
(Source: Tokyopop)
 
Note: Chapter count includes 7 extra chapters.

Akari Mizunashi continues her training to become a Prima Undine (a professional tour guide gondolier) along with her friends Aika and Alice in the peaceful city of Neo Venezia. Despite the fact that these three girls are from competing companies, they are constantly together, learning more about how to become better tour guides and more about the mysteries of Neo Venezia. 
As the group continues to meet interesting and unforgettable people through their daily routines, they will also come closer to the secrets that make the enigmatic and ever beautiful city of Neo Venezia so warm and alive. 
Welcome back to Neo Venezia: the city where miracles can be created by hand.

The first episode's story starts with Ai practicing on the gondola with Akari. As they travel through a canal, they meet Aika and Alice. All three have not had much time to meet since becoming Prima undines. Considering even the little time they spend together a "miracle," Akari remembers a certain incident and relates it to Ai. 
 
The second episode's story begins with Ai relating a story to Akari of her experiencing a "miracle" while she was practicing. She saw Cait Sith as she was traveling down an unfamiliar path. When she disembarks from her gondola to follow it, she meets two Single undines from Himeya company and Orange Planet in the middle of practice. 
 
(Source: Anime News Network)