Gargantia on the Verdurous Planet

In a far-off future, most of humanity has abandoned Earth and formed the Galactic Alliance of Humanity to expand into the stars. Their survival is threatened by the Hideauze, mysterious alien lifeforms that have pushed the Alliance into a brutal interstellar war. Sixteen-year-old lieutenant Ledo fights on the front lines alongside Chamber, his autonomous mecha, until a battle goes disastrously wrong and sends him drifting into deep space—ending with a crash landing on an ocean-covered Earth.

There, a massive seafaring fleet known as Gargantia salvages Chamber from the depths, assuming it’s valuable wreckage. Misreading their intentions as an attack, Ledo slips aboard and takes a young courier named Amy hostage, only to discover the people of Gargantia are far less hostile than he feared. Cut off from his comrades and forced to navigate an unfamiliar culture, Ledo begins adapting to life on the water—unaware that the planet still holds dangers beyond what he first sees.