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?

One morning, Akari wakes up to find the entire city flooded with water! It's the Acqua Alta, a once-a-year phenomenon where the water levels rise, causing all of Neo-Venezia to shut down for a day. But while most people spend the day relaxing, Aika's mentor Akira is as strict as ever, and yells at her to get back to training. Aika has just the solution to get her mentor off her back: she's running away to the Aria Company!

As winter melts into spring, Akari, Aika and Alice all continue to practice and set new goals for themselves. But Akari still feels like she isn't good enough to become a Prima. Will she or any of the girls ever be truly satisfied with their talents?

It's a double dose of President Aria! In "That Melancholy President...", it's cleaning time for the Aria Company, and President Aria wants to help out and lead by example for his company. Yet he can't seem to do anything right, and only gets in the way. He's so sad about it, that he's determined to run away... but where will he go? And in "That Cool Hero...", we get to see President Aria's cute crime-fighting alter-ego: Nyan-Nyan-Puu!

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?

A new vendor has opened up shop in Piazza San Marco, selling heart-shaped chocolates in glass bottles. Akari buys a bottle, and later goes to buy another, but by then, the patissier has mysteriously disappeared. Where did he go, and will he ever return?

As summer begins to wane, Alicia and Akari give a tour to an elderly couple who have come to Neo-Venezia to celebrate their anniversary. Although the woman is sweet and charming, the man is a bit of a grump. He orders her around, doesn't seem interested in sightseeing with his wife, and just acts cranky in general. But things aren't always as they appear... Even though he's tough on the outside, he still wants what's best for his wife, and it's up to the girls to help him set up a celebration that she'll remember always.

While training in a particularly tough stretch of water, Akari and Aika meet girl from Orange Planet who seems to be having no trouble at all. Her name is Alice, and she's famous for being one of the youngest yet most talented Undines in Neo Venezia. There's just one problem... she never seems to smile. What could she learn from a day spent with the unlikely pair of Akari and Akatsuki?

Alice is in a pretty bad mood. Her dorm doesn't allow pets but she's secretly taking care of a kitten; her mentor Athena is an absolute clutz; and to top it all off, she has decided that her left hand isn't as skilled as her right hand, and is therefore useless. Though Alice certainly does have a strange set of problems, and they all seem separate from each other, she's certain to discover that the answers to each all are connected.

Fall has arrived in Neo-Venezia and the girls have switched into their winter uniforms. And yet, Aika feels so unmotivated... She wants to do more than just go through the motions of everyday practice. She wants to really sharpen her skills, and become as good as the legendary Great Water Fairy, the greatest Undine of all time! So the three of them are sent to go visit this legendary lady in her house out in the country... but she's nothing like what the girls expect.

On one bleak winter day, when the clouds are thick and the snow is gently falling, the girls finish their sculling practice to find that Alicia, Aika and Athena are all together at the Aria Company, sitting around the fire. Over cups of hot cocoa, they discuss their younger days, and how it was that they all came to be friends.

Akari and Alicia are visiting a shrine that looks just like the old Japanese shrines on Manhome. Though the grounds are beautiful, there's also a hint of mystery and danger in the air... Later, they are wandering on a different island, looking for a beautiful spot that Alicia once saw. But the farther they go, the less certain their path becomes. How do you reach your destination when you don't know the way there?

Summer is blazing in Neo-Venezia. The days are so hot that Akari is starting to see things... One minute, she's walking down a crowded street, and the next, everyone is gone. Following President Aria in a haze, Akari wanders into a mysterious cafe, with a very unusual clientele... Later, the girls all decide to buy Nightshine Chimes, delicate little wind chimes with a glowing bead inside. The glow only lasts for a month before it fades, so Akari decides to make the most of the time she has.

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...

Akari has been given her very first solo job: carrying a shipment of Neo-Venezian glassware. They're beautiful pieces that sparkle in the sun, but the glassmaker's apprentice has a disposition that's anything but bright. He's sour and angry, and he's the one who'll be traveling with Akari as she delivers the shipment. Will Akari be able to handle the pressure of fragile cargo and a critical taskmaster?

Aika is proud of her long, beautiful hair, and takes care of it as best she can... but things don't always go the way we want. One afternoon, while everyone is enjoying a cook-out on the beach, Aika leans in a little too close to the grill, and her hair catches on fire! No one is hurt, but her long beautiful locks are a lost cause. How will the hot-tempered Aika handle losing something that was so precious to her?

Another wonderful holiday has arrived: Festa Del Bocolo! This day is a celebration of an ages-old story on Manhome, about a knight whose love for his lady lived on after his death in the form of a rose. In Neo-Venezia, that means that women everywhere receive roses from the people who admire them. Akatsuki wants to give Alicia as many roses as he can, but he's too nervous to deliver them (even though he'd never admit it). Will Akari be able to help?

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.

The whole town is sizzling in a strong summer heat wave, and the girls are doing the best they can to beat the heat. But then, Akari spots a woman dressed all in black, with even her face covered with a thick black veil. Aika tells Akari a Manhome legend about the spirit of a woman dressed in black, who was angered that she couldn't be buried on San Michele Island. Supposedly the ghost spirits away any gondolier foolish enough to take her on board... but that's only an old story, right?

Someone has requested Akari for a gondola tour! An old woman with a kind smile says that she'd like to see a side of Neo-Venezia that only Akari can show her. Akari takes her to many unique spots, but the woman already seems familiar with them all...

Akari, Aika and Alice decide to partake in an old Manhome tradition, Moon-watching. Aika secretly invited Al to their get-together, but he hasn't shown up yet. Aika goes to look for him, but she has no idea what surprises the night has in store.

Akari and President Aria are wandering through the marketplace one evening, when President Aria suddenly leads Akari to a plaza she's never seen before. There, a little girl with a bell around her neck gives Akari a letter, and asks her to deliver it. It seems very important. But if Akari's going to have any chance of keeping her promise, she'll have to enlist the help of flying messengers known as Sylphs!

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?

Akari, Aika and Alice are scheduled for a full day of training with Akira, and what's more, two customers will be along for the ride. They're a couple on their honeymoon; but while the wife loves Undines and riding on gondolas, the husband thinks being an Undine is simple work, and couldn't really care less about the whole thing. It's up to Akira to teach everyone what it means to be an Undine - Undines-in-training included!