The universe of Traveller is known space several thousand years in the future. Humankind has explored and settled over 11,000 worlds, and inhabits a volume of space hundreds of parsecs across. On its journey to the stars, it met dozens of alien races. It befriended some, warred on others, and maintained an uneasy distance from others still. It turned the worlds it owned into safe, pleasant technological wonderlands. Then, in less than a dozen years, greed and stupidity destroyed everything.
Now, 70 years later, small groups of humans are returning to the stars. The worlds they find, however, are much more dangerous places than they were less than a century earlier. There are a dozen ways to lose a ship, a hundred ways to die, and in lots of places only one way to get out with your skin. Most people play it safe. Most people stay dirtside, secure and comfortable. Most people are content to let history unfold as it will, and simply experience whatever life dishes up for them.
But not you. You’re different. You don’t much like the shape your ancestors left things in. And if you don’t like things, you do something about it. So what if doing something about it means changing the history of the universe? That’s the sort of difference that makes people leave solid rock behind to reach out and grab back the stars.