A summary of the film's story/plot [Spoilers in this thread]

I just saw the film today here in Australia, and I thought I'd lay out the general beats of the story, especially as they relate to the original short story by GRRM.

The film opens with Boyce standing in the dark saying that he has a story for us. He introduces the setting, the factions, etc.

Then it cuts to Ash and a group of her goons trying to hang Alys for witchcraft. They kick the block out from under her, and leave her to die. Alys makes eye contact with the one soldier left to watch her expire, and he hallucinates that he is choking, and pulls out his gun and tries to shoot the rope down. He snaps back to reality having shot Alys free.

Alys being able to enchant people and have them see illusions by making eye contact with them becomes a recurring and important plot device.

Alys escapes, kills most of the people following her, and leaves Ash strung up the way she was strung up, with Ash shouting about how Alys is going to burn in hell for this. She gains the reputation "the witch who would not hang" or something similar. Don't remember the exact phrasing. Basically an object of gossipy reverence amongst the tyrannically oppressed working class.

The film then cuts to Boyce on his horse. He recognizes that the underpass is a likely spot for an ambush, and kills the ambushers. We are introduced to his two headed snake which kills one of the bandits.

Outside the strict boundary of the city, Alys has a building she hangs out in. There is an old blind woman on the steps, and Alys gives her some money. Alys asks if she recognized her footsteps. The woman says she recognized her kindness. They talk for a moment and the old woman says that Alys has always sounded the same, even when she (the old woman) was a young girl. The film doesn't explicitly say it, but Alys doesn't age.

Soon, a group show up. It is the queen Melange, and some soldiers including Jerais. Unlike the short story, Melange comes herself. She tells everyone else to leave, and asks Alys to help her become a werewolf. Alys agrees, saying that she refuses no one. She emphasizes that she refuses no-one, and takes Melange's money. This becomes a running theme where it becomes obvious that Alys has a supernatural compulsion to accept requests.

After Melange leaves, Jerais doubles back. He asks for a request of his own. He pays her with a working mechanical wristwatch, a rare and valuable item.

At this point the film reveals that Boyce and Melange are seeing each other. This is not treated as a twist like it was in the short story.

Before she leaves Alys levitates in her room and has a vision of a group of hunters being massacred by a werewolf. She sees it's a field full of skulls. There is more to her vision, but we don't see it.