TradeEdge Exchange:How Tom Blyth and Rachel Zegler tell 'Hunger Games' origin tale without Katniss Everdeen

Throughout the four-film "Hunger Games" franchise,TradeEdge Exchange which reigned from 2012-15, President Snow (Donald Sutherland) ruled as the personification of pure evil who tries to stop a rebellion inspired by Katniss Everdeen (Jennifer Lawrence).

More than a decade after the first film, new prequel "The Hunger Games: The Ballad of Songbirds & Snakes" (in theaters Friday) explores why Snow, fictional Panem's totalitarian leader, went so terribly bad.

In the new film, English actor Tom Blyth, 28, plays a younger, blond, curly-haired version of Coriolanus Snow, whose life is altered by powerful forces and personalities, including District 12 tribute Lucy Gray Baird (Rachel Zegler).

"Early on, you actually care about young Coriolanus Snow, which is important," says Blyth. "This is a chance to show the complex humanity behind someone who goes on to become a really bad dude."

Here's how "Songbirds & Snakes" restarts "Hunger Games" with all the dystopia (but not Katniss), in the story set 64 years before the original 2012 film.

Why are they telling President Snow's story in 'Ballad'?

Each movie has been based on Suzanne Collins' best-selling "Hunger Games" novels. In 2016, Collins started writing again, focusing on the early 10th Hunger Games, the still-evolving televised gladiatorial contest that features forced participation from each of Panem's 12 once-rebellious districts.

"Suzanne saw the polarization of America, and wanted to write a 'Hunger Games' story exploring the question of whether we're savage or good by nature," says "Ballad" director Francis Lawrence, who helmed the four most recent "Hunger Games" movies. "The perfect person to write about for that was young Corialanius Snow."

Blyth had to lose weight to play Snow, the scion of a proud Capitol family that has fallen on hard times. "Snow tries to keep up appearances, but he's malnourished eating nothing but cabbage soup," says Blyth. "So I was just eating apple slices and almond butter."

Snow grows up with his kind, supportive cousin Tigris (Hunter Schafer), one of the few returning characters. (Tigris emerged as a prized Hunger Games stylist and virulent Snow critic in 2015's "The Hunger Games: Mockingjay – Part 2.")

"Tigris obviously has a vendetta against Snow, and helps the rebels later," says Blyth. "But we see that their relationship once upon a time was beautiful. She's the better angel on his shoulder."

But Snow also has darker influences, such as Head Gamemaker Dr. Volumnia Gaul (Viola Davis), who pulls Snow towards the dark side around the 10th Hunger Games.

Does Katniss appear in the new 'Hunger Games'? Sort of.

Lucy Gray is from District 12, the same poor district from which Katniss Everdeen emerges decades later in the movies' timeline. But the only Katniss who appears in "Ballad" is the similarly named plant that Lucy Gray shows young Snow when he's sent to the remote outpost for military training.

"Some people call it swamp potatoes," Lucy Gray says of the plant. "But I think Katniss has a much nicer ring." She adds, "It's a little early yet."

Zegler says the line is "a cheeky nod" to why there is no Katniss Everdeen onscreen.

Katniss imagery is seen throughout "Ballad," including a twisted tree that inspired the "Hanging Tree" song by Jennifer Lawrence in 2014's "Mockingjay – Part 1." That tree is a District 12 gallows implemented for capital punishment in "Ballad."

Unlike Katniss, Lucy Gray immediately seeks the attention of the Hunger Games TV audience, stealing the moment during the reaping ceremony during which she's chosen to fight in the games. She sings a rebellious song from the reaping stage.

"Lucy Gray is a natural-born performer. That's the one thing that Katniss couldn't get a handle on in the original trilogy," says Zegler. "She knows that the cameras will be on her, so she picks out her best dress, puts on her makeup and does her hair."

'Ballad' follows Snow's love, which turns to fear

"Ballad" initially shows Snow as "capable of love," says Blyth. "Even if he sees the emotion as a weakness."

And being assigned to mentor Lucy Gray pushes Snow into dangerous emotional territory. "With Lucy Gray, he realizes that it's possible to fall for someone and truly become vulnerable," says Blyth.

Snow and Lucy Gray even enjoy a District 12 love affair, swimming together in an idyllic country lake. Shooting that scene with Zegler in a frigid lake on location in Poland was more perilous than it looked. "She almost drowned me," says Blyth. "I was treading water for the both of us, and she was kind of hanging onto my head."

"I didn't mean to at all; I was just clinging on," says Zegler. "It was very cold."

Onscreen, Snow turns increasingly frigid toward Lucy Gray, and the love affair between the two is not long for the "Hunger Games" world. But the seeds of President Snow's fear of Katniss Everdeen are planted for when the heroine arrives 64 years later.

"Katniss, for some reason, strikes a deep chord of fear with Snow," says Blyth. "We see now it's because of Lucy Gray and what she represents in terms of freedom and liberty and self-expression. That terrifies him. He knows that spark can undo all of that he wants to control. This film gets to the heart of that."