A priest and his guardian come as missionaries to an Al Bhed camp, and the Al Bhed are going to do everything they can to convince the Yevonites to leave.

2022 note For a take that interprets “fallen summoner” to mean that Braska was already a summoner before his fall from grace, I can recommend [this fic]. There’s a lovely scene where teenage Auron gets drunk and falls off a bench.