A mountain spirit is strangely attracted to the club members of the Roman club in the high school near her shrine … and thus begins all their adventures into the unknown.

Hikari Kohinata is a cheerful 15 year-old girl who lives near the ocean and she spends much of her time diving as a result. On her first day of high school, she meets a teacher who also likes scuba diving. There's also a 16 year-old classmate, Futaba, who gets dragged along in Hikari's maelstrom as soon as they meet at school. Most of the manga so far details the relationship between the two girls, which quickly seems to move into romantic two girl friendship-territory.

From Tokyopop:
After 150 years of terraforming, Aqua, the planet formerly known as Mars, now has over 90% of its surface covered by water. A young girl named Akari Mizunashi arrives at the city of Neo-Venezia, an exact replica of the old Italian city of Venice, hoping to become an Undine, the most coveted job on Aqua. Follow Akari's adventures as she discovers the wonders of Aria in this prequel to the popular Aria anime and manga series.

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. The technology of "Man Home" (formerly Earth) has not entirely reached this planet, and Akari is alone, having no contact with family or friends. Nonetheless, the town, with its charming labyrinths of rivers and canals, becomes Akari's new infatuation, along with the dream of becoming a full-fledged gondolier. Reverting to a more "primitive" lifestyle and pursuing a new trade, the character of Akari becomes both adventurous and heartwarming all at once.

(Source: ADV)

Invanders from an unknown dimension prey on the loneliness of the human soul. The only thing between them and the success of their diabolical plan is 4 youngsters with powers to rival the invaders!