The sun was dying and in order to survive humanity constructed interstellar arks with millions of people in suspended animation and sent them off, bound for different star systems that might be able to support life.
One ark was supposed to go to a nearby star, but when the passengers were awoken they were in a super-giant planetary system made up of four stars (Alpha, Beta, Gamma, Delta) orbiting a black hole (Omega). Each star has dozens of habitable planets. Collectively, the super-system is called The Quad. The Quad is inside a huge nebula that interferes with outside signals.