“The Faithful” is episode four of season three of Supergirl.
A man on a plane is drinking and talking to the man in the seat next to him; he sounds as if his life has fallen apart and he’s bitter. Then the plane runs into problems as an engine catches fire. It doesn’t crash, but splashes down into the water. Then Alex stands up, because this is the incident from “Pilot”. The first man sees Kara standing on the wing, then she flies off.
Two years later and Samantha is at a football match where Ruby is playing when a woman comes over to her. The woman knows Ruby’s name and says she’s special. Chosen. As is Sam. She hands Sam a leaflet and says to bring Ruby to their community so she may learn her path.
Lena and Kara arrive at Lena’s old office, then are joined by Sam, who as the new CFO talks about a merger. Kara invites Sam to girls’ night and she’s convinced to come. Then Kara sees the leaflet; she recognises something and asks to keep it.
James and Winn are heading out from CatCo when they see Kara at her desk. Winn sees the leaflet. The thing Kara recognised is the Kryptonian symbol for Rao. Kara has been trying to find out why it’s on the pamphlet. All that’s inside is a time and address. All three head there.
The meeting is being run by the man from the plane. He welcomes them, saying they are all there by her grace. Supergirl saved them. Kara recognises a prayer he says. A young woman gets up and explains how Supergirl saved her. James asks Kara if she remembers. Kara remembers saving them all. And they’re all praying. To her.
At the DEO, it seems the man leading the meeting, Thomas Coville, had his life fall apart three years ago. Kara doesn’t remember saving him, but Winn explains he was on the plane. Kara says Colville is twisting the teachings of Rao. Winn asks how he knows them.
At girls’ night, Maggie mentions she and Alex aren’t going to have children. Though Alex does not seem keen. Then Kara hears sirens and heads to a fire where she catches a man on the roof as it collapses. He says he was waiting for her and kneels, and the young woman from the meeting says he’s one of them now.
Maggie arrives and Supergirl explains about the cult and how people are putting themselves at risk thanks to Colville. Maggie explains that so far Colville hasn’t broken the law.
Kara returns to the meeting room and speaks to Colville, saying she’s from CatCo working on a story about Colville’s religion. She asks about the arsonist. Colville thinks she’s there to test his faith. As he knows she’s Supergirl.
Colville not only knows who Kara is, he’s been collecting Kryptonian artefacts and truly believes that Supergirl is a god of some kind. Which means he’s got a dangerous level of faith in her and wants others to be saved like he and the others were. Saved from certain death by Supergirl. Which makes him dangerous.