Codename: Antidote

I accidentally broke into another space. There was no one but myself. I was searching for a way back in despair, but I found a group of people, a group of dead people. Who were they and where did they come from? Why don't you look the same as me? How do I get out? It turns out that this place is just a transit station, and there is a bigger world behind it, with more people and a higher level of technology. I accidentally broke into my world and got involved in their disputes.