Originally Posted by mr_dad
Looks very promising. Only..
..I don't want to sound like I'm trying to ruin the idea, but this sounds an awful lot like Mass Effect's plot. It can be different if you do it right, I just want you to know, be careful. That being said. Good luck
BioWare did not invent that with Mass Effect, neither did Halo or any game.
The original concept (as far as I know) came from Ridley Scott's ALIEN where it was proposed the ship was a bombing vessel used to infest planets with the Xenomorphs cleansing them of life.
Even then you could say the idea goes back even farther to the myth of Pandora's Box where the Olympian gods needed to cleanse Earth of all life.
Now more so than recently, the idea has become quite popular with just about everything from games to shows. Halo, Mass Effect, Dead Space just to name a few games. Game of Thrones even has a similar thing with the White Walkers.