Stardust Wanted: Secrets from the Frontier of Civilization

Humanity has entered the "Stardust Era" and established a huge colonial empire "Human Star Federation" (HSF) in the galaxy through faster-than-light navigation technology. The Federation has been in contact with multiple alien civilizations, and their relationships are complicated. There are fragile peace agreements and local conflicts caused by competition for resources. The core of the story revolves around an ancient alien ruin called "Umbra", which is said to contain secrets that can change the balance of power in the galaxy.