This was a bit of a struggle, being twice as long as its limited ambition requires - that ambition being to illustrate the weakness, fallability and moral confusion of a Catholic priest, tempered by a hint of hope. At least this was acheived.
The setting is a Southern State of Mexico where a deadly Catholic purge has been underway for ten years. The churches have burned and the priests have fled, or been killed, or renounced their vocations - except for one. Quite how such a stupid, vacilating character managed to evade capture for so long is beyond comprehension, but nevermind - even more frustrating is that the situation is never explained. Why is the purge happening? Why is it State-wide but not Nation-wide? What year is it, anyway? Why are distilled spirits and wine illegal when beer is legal? I don't know if ignoring all this was meant to make the story more like a parable or if Greene's obsession with Catholic angst just rendered all context unimportant to him, but for me it was a missed opportunity.