Suisei no Gargantia

In a distant future, the Human Galactic Alliance has been engaged in a desperate struggle for survival against the Hidiaazu, a monstrous alien species. During a fierce battle, Lieutenant Ledo and his humanoid mobile weapon, Chamber, are pulled into a distortion of space and time. Upon awakening from his artificially induced hibernation, Ledo finds himself on Earth, a planet on the fringes of the galaxy. The planet's surface is submerged beneath the seas, and its inhabitants eke out a meager existence in massive fleets of ships. These vessels, known as the Gargantia fleet, scavenge the depths of the ocean for resources and relics to sustain their precarious way of life. Ledo's arrival on the Gargantia fleet sets in motion a series of events that will challenge his perceptions and force him to adapt to a world of peace, a notion that is as alien to him as the planet itself. As he navigates this unfamiliar environment, Ledo is drawn into the lives of the people around him, particularly Amy, a 15-year-old girl who serves as a messenger on the Gargantia fleet. Her innocence and optimism serve as a counterpoint to Ledo's war-weary worldview, and the contrast between their experiences will shape the course of their lives.