In the distant future, Earth's natural resources have been exhausted, and humanity depends on colonies elsewhere in the Solar System, overseen by an alliance that manages trade, travel, and space settlement while a defense organization protects Earth and its interests. A breakaway militant faction known as the Settlement Defense Front, which seceded from Earth decades earlier, seeks to seize control of these outlying colonies and threatens to plunge the system into war. When the Front launches a devastating attack, pilot Nick Reyes unexpectedly becomes captain of the warship Retribution and must lead its crew across planets, moons, and asteroids to hold back the enemy advance.