Vein of Time

In 2749 AD, humans discovered that "time entropy" could be extracted, solidified and used as energy. Prehistoric civilization left "time veins" all over the major planets in the solar system. The "time crystals" mined can drive interstellar spacecraft, reverse local aging, and even suspend regional time. But over-exploitation can trigger a "time sandstorm" that drags the entire area into a random past or future. Humanity is divided into three major forces: the "Star Federation" that monopolizes the veins of time, the "surface survivors" struggling in the wasteland, and the "Temporal Order" who believe in "the sanctity of time."