What's left of Rave Rough

The year is 50XX, humanity is gone and the only remanence of them is music. Aliens invaded Earth a while after the extinction and built their society around humanity's music culture. However that's wayyy too much dramatic backstory! In the present, the biggest musician in the world is holding a massive contest. The prize? The Ultimate Sample CD!! Whoever gets to the top of his private HQ first, wins! This little contest gets the attention of mania amateur DJ, including our protagonist Scat who'll do anything for it!