In 2137, a solar flare kills millions and spreads a dense plasma called the Sea of Geduld across the solar system. In 2225, teenage cadets learn to navigate around this deadly obstacle at a training center on the edge of the Geduld Sea. Sabotage during a routine dive procedure sends the space station plummenting into the Geduld. With all the adult crew and instructors killed during the evacuation, the young astronauts must rely on their training and each other to survive the journey home.