Attention Challis

I just learned an amazing fact about a secret high society club that we're both in. It's so secret that I can't mention the name on this page...however, here's a clue. I just got off the phone with our mutual Frontier friend, and the initials of the club are the A.P.C.
If you figure it out, don't write it on here, or she'll kill us both. Then there would be no more A.P.C.