You joined the Brigade about thirty years ago, when they were on a mission to Earth. Their trail of the infamous Space Pirates had led them to Hollywood, where you were at the time, and you found out what was really going on. You were intrigued -- it was the first real excitement you'd had in ten years. You could see where your career was heading: though your voice hadn't faded, your inspiration was starting to, and the last thing you wanted was to end as some sort of lounge lizard. When you found out that the aliens had life-extension technologies, as well as adventure and purpose, you knew you'd found your niche. You asked Johnny, one of your hardest-core fans and a friend, if he would take your place for a while, to cover your escape into outer space. (Since one of the rules that the Brigade set down was that you couldn't let Earth know -- the world was still too primitive and violent for Contact.) He was good with almost all of your numbers, and looked close enough to you to be mistaken for a brother; with a little creative cosmetics, you figured no one would notice for a while.
What you didn't expect was how much they liked to rock. The Galactic Republic was a generally good place, but not exactly the height of musical inspiration. Indeed, you discovered that the main crime of the Space Pirates was spreading Gilbert and Sullivan to the stars -- apparently, a few aliens had been part of the original company of Pirates of Penzance, and were quite taken with it, taking the music back to the cosmos. You can't condone their methods (they've killed more than a few people with their antics), but it isn't as if G&S is all that bad -- you sort of like it, really.
But when you pulled out your guitar and started to rock, they were rapt. They had never heard anything like Rock and Roll, and were clearly hungry for it. Within months, you had groupies all over the Galactic Arm, sometimes getting in the way of getting your work done. You figured it was a fad, and would wear off before long, but it's continued for decades. It seems like no one outside of Earth has any real musical creativity, so once the rest of the Galaxy latches onto something, they can hold it for hundreds of years. It's a blast, having trillions of devoted fans, but truth to tell, it gets kind of tiring sometimes.
And now you're back on Earth, and it's even weirder than outer space ever was. How can the world change so much in only 30 years? Remarkable advances in technology (although still incredibly primitive when it comes to spaceflight); strangely-fluid politics, quite different from the comfortable certainties you grew up with; your daughter marrying this strange freak (although at least she wised up eventually); and the music! Man, what is some of this noise? Some of it's recognizable as rock, but the rest is just loud! And it's kinda sad to learn how poor Johnny ended up: fat and dissolute in Las Vegas, just as you were afraid you'd end. It's actually a little embarassing to have people believing that you died on the toilet.
And then there's this cult that seems to have grown up around you. It's one thing to have groupies; that's normal and natural. But you've got a religous side, and the notion of this "Church of Elvis" you've been hearing about makes you awfully uncomfortable. You really want to find some way to convince these folks that you're just a man with a guitar, not some kind of God. They need to learn to live their own lives, and make their own music. Heck, some of 'em might even make decent Space Brigadiers, if they can learn to think for themselves...
(Still and all, they might make useful allies. You're trying to track down this band of Pirates that has landed on Earth, and having some people on your side who know the lay of the land could help a lot.)