You would be inside the great underwater city of Rapture, just making your way around while trying to avoid splicers; all you're armed with is a dinky rusted snub-nosed revolver. After wandering around, trying to find a way off of Rapture, you make it to a large and empty atrium with a good window view of the ocean and a bit of Rapture's exterior. Suddenly you hear a loud, ear-piercing screech; it's so loud you can't tell where it’s coming from. You frantically go to grab your weapon when you see a glowing red light in the corner of the atrium room. It jumps down from the banister it was standing on previously on top of you, knocking your only form of defense from your hand.

Big Sister: Just stares at you, not saying anything as Big Sister don't speak