The story mainly explains itself through text logs, interviews and audio logs.

The Cube

An alien cubic space station, the Nexus, is a platform, which source is unknown and will be explored through the game.
It is like the cube from the movie "the cube", which is built by multiple smaller cubes.

The station is a collector and a hive mind of all civilizations visited.
It is not a single big cube, instead there are thousands of smaller cubes, which are combined the big cube.

The Smaller Cubes

Every cube represents a civilization mind and tries to help or destroy the players.
The smaller cubes holds one single big room, which can have smaller rooms inside and vary by alot in environmental conditions and represents all visited worlds from the station.

Some cubes are not part of the big one and flew few miles in distance around the cube without any pattern.
This are the cubes, the players are spawning ingame.
This cubes can dock to any other cube.
So this is the "choosing a level" mechanic.
You can only select cubes which you have codes for.
Except one.
This is the entry cube for the big cube.
The smaller cubes are connected through hallways inside of the big cube, so they are the levels and explains, why some level or mechanics are being reused or have alternatives routes.

The inner environment of such cubes are very earth-like.
There are trees, a small house and a blue sky.
So everybody feels warmth and healthy.

The Player

The player is a human being from earth, which was sent to investigate the station.
But as they arrive, there was a light and they forgot everything.
They wake up in a sleep pod when they join a server.
At the beginning, the cube they spawn IS the collector for the mind.
It tries to learn from them though testing and how they interact with other cubes.
It is the control room to select missions and equipment.

The server lobby mechanic is symbolized through the flying cubes connecting to each other.
The host is the one, where everyone connects to.

Creatures

Most cubes holds creatures, mostly aggressive.
A lot are the same, because they overtaken the cubes.
In the story, it says that this are intruders like the humans.
But the cube is a testing facility, so this creatures are testing subjects like the humans.
Nothing else.
The player should get the feeling, that he helps to clean.
The big cubes asks them for this in multiple places ingame.