It began with what seemed like a chance encounter with a radio show I don’t usually listen to.

WROL AM 950 in Boston came on, playing In Season and Out of Season, a Catholic program hosted by a priest of the Archdiocese of Boston. A voice I didn’t recognize described an incident in which the speaker had suddenly felt called to talk about God to people standing in line at a palm-reading establishment in Salem, Massachusetts, the unofficial Halloween capital of America.

That got me thinking, “What’s it like to be a Catholic in Salem in October?”

A few months later, I was standing near the voice on the radio, a lay Catholic street preacher, on a warm Saturday afternoon a few days before Halloween. I spent about two hours with him, most of it watching, including a memorable 11-minute exchange with a Satanist.

Afterward, I walked to a Catholic church downtown that keeps its doors open (not just unlocked, but wide open) with an exposed Host on the altar for hours at a time during Halloween season.

About a million people visit Salem every October, many of them dressed in black and many of them presenting as witches, vampires or devils.

“And that part is a little disconcerting,” the pastor of the church told me.

“Our Catholic response,” he said, “is that we invite people to come in and find some peace, to sit and rest.”