NPA is Non Prosecute Agreement = Immunity. Most all of them got one. Notice the part about the "prominent politicians."

http://www.browardpalmbeach.com/news/in-jeffrey-epstein-underage-sex-case-woman-says-she-was-forced-to-have-sex-with-prince-andrew-alan-dershowitz-and-world-leaders-6437694

Decent summery of the original document.

This shit is fucking crazy deep. I can't believe he only got a single charge of prostitution and served 13 months on a plea deal. Weed smokers get more time than that.