Carolyn Keene 
Dance Till You Die [EPUB ebook] 

Bess has landed a job at the Razors Edge dance club, and shes invited Nancy to check it out. With a wild young crowd, crazy costumes, and a handsome DJ, its the kind of place where anything can happenand soon does. When the lights go out and someone screams, no one knows what is happening. But as soon as the blackout is over, Nancy makes a shocking discovery: Bess has disappeared!