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!

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?

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?

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.

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!

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!

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.

Winter has come - the mornings are crisp and cold, and it's hard to get out from under the covers to go practice sculling. So as a special treat, Alicia suggests that they visit a hot spring! Akari's never seen one before so she's excited to go, and all the others decide to join in as well.

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.

Aria Company has no bookings on a snowy day, so Akari and President Aria visit the oldest bridge in Neo-Venezia. When they reach the other side of the decrepit covered bridge, the snow is gone, and the women she meets on the other side has no idea what an undine is. Together they wait for the terraformers to send water under the bridge for the first time.

It's time to ring in the new year, and everyone in Neo-Venezia has come together to celebrate! Even little Ai has come back from Manhome to take part in the winter festival. But as people gather and memories are shared, President Aria suddenly wanders off. Akari and Ai attempt to track him down, but what they find is a mysterious New Year's gift from Aqua itself.

Spring is beginning to bloom in Neo-Venezia, bringing with it sunshine and warm breezes. Akari, Aika and Alice are out practicing their sculling when they find a small treasure box hidden by a statue. Inside there's a a simple little riddle that sends them off on a treasure hunt that spans the entire city! What sort of riches await them at the finish line?

The mailman's gondola is being repaired, so just for today, Akari is making the rounds with him to get the job done. As she learns the ins and outs of what it means to be a mail carrier, she meets a boy who needs his letter delivered at any cost. Whatever the envelope he's holding contains, it's very close to his heart.

Something's strange about Alice... Athena has noticed that Alice doesn't really seem to have any friends her own age. If she's not with Akari and Aika, she's simply alone. In fact, when Alice receives an invitation to a party with other Orange Planet Pairs, she flatly rejects it. It's up to Aika and Akari to get to the bottom of Alice's puzzling behavior.

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?

Even though Akari is originally from Manhome, she seems to know more people in Neo-Venezia than Aika and Alice do, and they've lived on Aqua all their lives. No matter where she is, Akari has the ability to befriend any stranger. To learn more about this mysterious power Akari has, Aika and Alice decide to follow her in secret... but they might have to blow their cover once Akari innocently starts talking to a dangerous-looking man in black!

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.

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.

When Akari takes her gondola in for a routine inspection, she's given some startling news - the repairman tells her that the gondola is now too old and worn for tourism use, and should be sold off for hauling cargo. Although she at first resists, Akari knows that the repairman is right; so she decides to travel with her gondola to all the wonderful places that she's been, as a way of saying goodbye.

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?

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?