You must now fight for your survival by any means necessary. You must forage and hunt for food as well as protect yourself from wild animals and possibly other people trapped inside with you. You must find shelter to survive the unforgiving nights. As you do so, you will very likely encroach on the demesne claimed by someone other than you. The animals of the wild have laid claim to this forgotten land. This is now their demesne. You’re in their world, now.