Drift peacefully into Neo Venezia, a city on the planet Aqua (formerly known as Mars). By the 24th century, humans have found a way to colonize the previously uninhabitable planet. As futuristic as that sounds, Neo Venezia is still teeming with rustic beauty; gondolas on wide canals and waterways are the main mode of transportation. The city itself is a faithful replication of Manhome's (the planet formerly known as Earth) Venice. To make sure that residents and tourists alike get the most from Neo Venezia's many wonders, companies offering guided tours via gondola were formed, one of which is named Aria Company. This is the workplace of Akari Mizunashi, a free spirited teenager from Manhome who is now a novice Undine (the title given to tour guides). Join Akari as she becomes intimately acquainted with other Undine, tourists, Neo Venezia's residents, and even the city itself, learning many valuable life lessons along the way, such as the wonderful truth that there are such things as manmade miracles.

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.

Four years into the future, the world has lost its balance... 10 thousand metres of vast woodland is gone, preventing humans to live and leaving a desert to spread endlessly. And so, they head into the world of Meshichi, to live together with the Anbots. As if guided by fate, Sanzou and Gokyuu meet. Traveling together, Sanzou - a young man shrouded in mystery, Gokyuu - the strongest and worst Anbot around, Tongoh - an Anbot fond of drinking, Jou - someone who is great with machines, Suuji - a female Anbot thief, and last but not least, Mioto. And so, their journey begins to the boundless East, to the land where the sun was born! (Source: AnimeNfo)

Following the first season, Tomoharu is now faced with a dilemma: if he doesn't form a contract with an akuma, he risks losing his dear friend Takatsuki. However, doing so would compromise his own existence as it would result in him and his ghost friend Misao becoming an Asura Cryin'—mankind's biggest threat, according to their school's presidents. To make the decision even harder, Tomoharu and Misao have recovered some of their past memories—memories of a world that they didn't even know existed.