Soul Music - Discworld Novels by Terry Pratchett

This is a story about sex and drugs and Music With Rocks In.
Well…one out of three ain’t bad.

Being sixteen is always difficult, even more so when there’s a Death in the family. After all, it's hard to grow up normally when Grandfather rides a white horse and wields a scythe. Especially if he decides to take a well-earned moment to uncover the meaning of life and discover himself in the process, so that you have to take over the family business, and everyone mistakes you for the Tooth Fairy.

And especially when you have to face the new and addictive music that has entered Discworld. It's lawless. It changes people. It's got a beat and you can dance to it.

It's called Music With Rocks In.