The premise is pretty simple; you
play as a crew member aboard a spaceship, and there are impostors among the crew (up to 3, depending on server settings and the number of players), who try to sabotage the ship and kill everyone inside. As a crewmate, you have tasks to complete; completing all tasks makes the crew win, though you can also try to figure out who the impostors are in order to eject them. As impostor, like I mentioned, you get to sabotage the ship, and your main goal is to kill everybody; you can also use vents to hide, and even during voting sessions, you can try to convince the
crewmates that someone else is the impostor, and have them ejected.