[NTG-context] Reference to prologue becomes "Chapter 1"

I have a chapter in the frontmatter that has no chapter number. The first chapter in the real book is Chapter 1. But when I refer to \in{chapter}[prologue], what I get is "chapter 1". Is there a way I can make \in{chapter}[prologue] return something like "the prologue"? I'm using mkii G