This is a modded modern apocalypse survival server called Parasitus. The whole thing is set in a quarantined zone named Alpigus and it feels like a horror story that is actually happening.
For the first 7 days everyone is trapped inside the zone while the quarantine wall still has power. When the grid fails the wall opens and the Nether unlocks and the End becomes reachable so the server suddenly gets way bigger.
There is also a huge deadline where a nuke drops inside the wall and wipes everything in the zone. If you do not escape in time you are basically finished.
It is not hardcore and there is land claim so people cannot grief or force PVP on you. But it does not stop stealing and PVP can be toggled in claims with commands so you still have to be careful.
