This story, in the universe of Suisei no Gargantia, follows Bellows, a side character in the original series, where the planet is covered with water and humanity lives in various large fleets of ships. The story begins three years before Ledo (from a spacefaring civilization) arrives. When Bellow's fleet is destroyed, she is rescued by a fleet of salvage ships, which send teams of yumboros (human operated excavation robots) under the water to recover goods. Her skill with yumboros is valued by her new fleet, and she soon joins the salvaging team.
Ledo is living his new life with his companions aboard the Gargantia fleet, and he works diligently as a member of the salvage team working to recover bits and pieces of the previous age of human civilization. Reema, a girl who used to be a part of Cugel's fleet, then appears. Reema now studies under Amy as a messenger. After Ledo and Reema meet, Ledo reflects on his former life in the military and how the life he lives now aboard the Gargantia is completely different. Ledo is also awaiting the difficulties and crises that he knows the future will bring. With his bond with Chamber engraved on his heart, Ledo faces his future in the sky and in the sea. (Source: Anime News Network)
Side Story
The story begins in the distant future in the far reaches of the galaxy. The Human Galactic Alliance has been constantly fighting for its survival against a grotesque race of beings called "Hidiaazu." During an intense battle, the young lieutenant Ledo and his humanoid mobile weapon Chamber are swallowed up into a distortion of time and space. Waking from his artificially induced hibernation, Ledo realizes that he has arrived on Earth, the planet on the lost frontier. On this planet that was completely flooded by the seas, people live in fleets of giant ships, salvaging relics from the seas' depths in order to survive. Ledo arrives on one of the fleets called Gargantia. With no knowledge of the planet's history or culture, he is forced to live alongside Amy, a 15-year-old girl who serves as a messenger aboard the Gargantia fleet. To Ledo, who has lived a life where he knows nothing but fighting, these days of peace continue to surprise him. (Source: Anime News Network)
