Akari Mizunashi, at the age of 15, has left everything behind to travel to Aqua, a sparkling planet covered in water. More than anything, Akari wants to be an "undine" - a female gondolier who navigates the canals of the Aquan city of Neo-Venezia. As she begins her training with the prestigious Aria Company, will she be up to the challenges that await her on the path to achieve her dream?

When Akari was little, she was certain that Neverland was a real place. As she grew up, she understood that it was fantasy... But now, she's received a mysterious, hand-written invitation to visit Neverland for herself! What awaits her as she follows her map toward a quiet, deserted island?

Two wonderful things have happened: it's time for Neo-Venezia's annual Carnevale, and Ai has come back to Aqua for a visit! As Akari and Ai wander through streets full of bright colors and beautiful masks, they catch a glimpse of Casanova, the mysterious master of ceremonies. Who is the man behind the mask? The two are curious, but they'll need to be careful. You know what they say about curiosity and the cat, after all...

While practicing one day, the girls see President Aria in his own little gondola. But he doesn't see them... instead, he disappears down a canal that's normally closed off. According to Alicia, there's an old legend on Manhome that tells of the Kingdom of Cats, a strange realm that people aren't allowed to enter. Could such a place really exist?

Alice has created a new challenge for herself: when she walks home from school, she can only step on shadows. This is an ironclad law for her - but try as she might, she keeps failing. Even worse, Athena interferes by trying to help out. Alice's self-imposed challenge is something that she must conquer alone, or so she thinks; but maybe there's more to success than just doing everything by yourself.

Many of the water touring companies in Neo-Venezia have their own palina - a tall, decorated pole used to hitch gondolas. But strangely, the Aria Company doesn't have one. When Akari asks Alicia about it, Alicia gives her full permission to make a palina of her own! It's tough work building something from scratch, but Akari is determined to make the best palina possible.

In the still of the night, Akari is woken up by the distant sound of a train. But Neo-Venezia's trains don't run at that hour, so what was it she heard? And to make matters even more mysterious, the next day, President Aria gifts her with a train ticket. It would seem Akari is about to have another brush with the secretive spirit, Cait Sith...

As snow softly covers Neo-Venezia, Akari and Alicia are out for a walk. Akari asks Alicia what she thought as a child - back then, what did she want to be like when she grew up? But in response, Alicia just begins to roll a ball of snow on the ground. As they walk around the city pushing the snowball, it grows bigger and bigger, to the point where people remark on it everywhere they go. Alicia only continues to smile, but it's certain that her answer is hidden there somewhere.

Akari finds herself nervous coaching a new undine as a Prima, until she awakens to find that it is just a dream. To soothe her worries, Alicia recalls stories of her beginnings as a Prima, as well as the memories she made.

Akari and Alicia are going to visit Anna, the woman who trained with Alicia in the early days of the Aria Company! Many memories will be shared on this visit, including how the Aria Company itself was first founded.