The Jewels of Elsewhen

You are riding home from work on the subway. There is a jolt - and as you fall against your neighbour you discover - he is a manikin.
You investigate. The entire train is filled with manikins. Are there no humans in this world...?
You approach a door. There is only an opaque blackness on the other side. You are wary. You put through only one arm. It disappears completely. You are curious. You must find out what lies beyond.
You walk through the door into the void...