The saga of The Witcher is not an easy one to adapt. The Witcher games (with which you're no doubt familiar) had it simpler--as sequels to the original novels, they simply built on the foundation that author Andrzej Sapkowski laid down years ago. To adapt the book series--a hodgepodgey web of short stories and novels--into hour-long TV episodes with a trio of protagonists and a cohesive narrative throughline is a significantly different story.

Netflix's The Witcher showrunner, Lauren Schmidt Hissrich, is the person who had to solve that problem.

"To me, there are challenges, and there are opportunities. And this, to me, was such a great opportunity," the showrunner told GameSpot during a recent interview. "You have all of these short stories presented in the first couple of books, in The Last Wish and in Sword of Destiny. There is no narrative thread between them, so Geralt doesn't grow and change that much between the stories, because that's not how they were originally written."

"Well to me," she continued, "if you're adapting those for television and you're going from episode 101 to episode 108, you need to see the character grow and change from his or her experiences."

The resulting show takes those short stories--tales like The Lesser Evil, A Question of Price, and The Edge of the World--and remixes them into a cohesive story with a beginning, a middle, and an end. The stories are perfectly recognizable to fans of the books, but they take place in a different order and sometimes involve different characters. And Schmidt Hissrich ensured there are throughlines that span the eight-episode first season.

"It was very important for me to start with The Lesser Evil as the first story," Schmidt Hissrich said. "You're starting with a character who's been living, let's say, close to a hundred years. He's a Witcher. This is all he's ever done. It's what he was trained to do. Does he love it? Who knows? We don't even care. It's just what he's best at. So he continues going back to it. And then we need to have something happen in that first episode that totally corrupts his worldview."

The events of that first episode follow Geralt throughout the rest of the season--not in a way that's necessarily faithful to the source material, but in a way that enhances this version of the story.

"We very much had a sense of the stories that we wanted to tell. Some of them were just our favorites, or some of them were very iconic," the showrunner said. "It was really about taking the stories that were iconic and we wanted to tell them, and sort of tracking Geralt's journey. And it was very interesting to work with Henry through that too, because he read the same books that I did. So a lot of it was talking out our reasoning of why this is happening now, and not back then. What I think what we've done is craft a season for all of the characters."

That's another massive change: While the original short stories, on which most of this season is based, put Geralt front and center, Netflix's The Witcher is a three-pronged story with a trio of main characters: Geralt, Yennefer, and Ciri. Schmidt Hissrich's other big challenge--err, opportunity--was figuring out how to weave all three characters' plots together. She came up with a variety of solutions; for example, the Yennefer we meet in the show is much younger than the person Geralt first encountered in the story The Last Wish. The show spends several episodes exploring Yennefer's backstory over many years--a backstory that was invented for the Netflix version of events.

That story came with its own unique hurdles. After the physical transformation that Yennefer undergoes when she becomes a sorceress, the character stops visibly aging--but she continues to mature emotionally, something actress Anya Chalotra had to convey.

Read more: Netflix's Witcher Showrunner Lauren Schmidt Hissrich Says They Won't Adapt The Games

"She stays in her 20-year-old body, and so I had to figure out a way to make this believable," Chalotra told us. "She does get older, and she does get more mature, and her thoughts do change, and her attitudes change toward certain things. She responds differently to things because of the life experience she's had. And I think I did that through breath...there's a rhythm and an energy that people have who are older and have been through something, certain experiences."

For Ciri's part, actress Freya Allan contended with something similar. Ciri begins life as a princess who believes she's wise to the ways of the world, but finds out she has plenty to learn when her life gets thrown into chaos. Ciri's arc in Season 1 is a transformation all its own.

"She's got a very kind of bold, strong character right from the beginning. But then when she is thrown into this world, you do see her become vulnerable, but obviously she still has those built-in characteristics that we see right at the beginning in her, and that's what allows her to keep going," Allan said. "It was interesting to look at that, and also how the brutality of the world changes her and she becomes colder...definitely toward the end, you get to see that she decides, she's like, 'I'm sick of this now. I'm going to just--I'm just sick of it.' And she starts becoming a bit icier."

The ways all these disparate storylines and characters come together will have to remain a mystery until The Witcher hits Netflix on December 20. But Schmidt Hissrich said the show's first season feels like "hitting the first domino and seeing them fall over"--and she promised "some surprises for existing fans" as well. We can't wait.