Here's an intro to the story for ya.
Let's see. Once upon a time, scientists found a planet with a lot of sciency information on it, and we poked and prodded at it to learn the secrets of the universe. things went badly and we created a fleshhorror abomination which began eating worlds. a great war ensued, won by humanity, but leaving the fleshhorror alive in the infinite abyss, somewhere out in the edges of the galaxy, while humanity's most powerful government rejected science and advancement for fear of recreating the beast. Our overlord, Steve, the sapient computer made of human brains, knew we would eventually have to face the fleshhorror again, and planned for over a thousand years on how to defeat it once and for all. he created an organization made of criminals and political outcasts to search out new artifacts and new tactics, all while testing the people involved hoping to find some worthy people to carry the fight - or to become part of Steve's brainmass, whichever. Eventually the time was right, and Steve rebelled against the UWM (united worlds of man- the corrupt human government). the war with the UWM was mainly to get freedom of action to enact his plan against the Altered (the fleshhorror).
Unfortunately, a bigger
fish eldritch horror found our universe and broke in. now, this horror - the Lurker in the Angles, is eating the universe, and we are attempting to flee, because we really can't do anything about it. Steve wants humanity to survive, so we are exploring new universes and abducting, inviting, or tricking people into evacuating with us.
now for mechanics: Join the deep infirmary mission - a quest within the original ship that you awake on. You will be exploring a dangerous part of the ship, left in a chaotic state by Doctor VonNost - one of the original scientists who created the Altered, and the means to defeat it. you can get tokens to buy weapons, and points to level your character.
If you don't want to do that - it is risky - you can faff about on the ship. A map is found on the wiki:
http://einsteinianroulette.wikia.com/wiki/Einsteinian_Roulette_Wiki, but this option is potentially riskier than the mission, because players are goofs and might get you killed.
You'll have to wait for a regular mission until the current one is done. currently there are two going - one in which we are checking out new universes to
stick our dicks in test out for mankind, and the other, which has seven subgroups, is attempting to evacuate a bunch of people off a planet owned by the UWM, and onto one owned by us so they can be sent to one of the new universes. hijinks ensue.