• Netflix's "American Primeval" is inspired by the true story of the Mountain Meadows Massacre.
• The massacre is depicted in episode 1 and is the inciting incident for the main characters' journey.
• The real-life tragedy took place in 1857 in Utah. 120 people were murdered.

Netflix's dark new Western series, "American Primeval," draws inspiration from a real-life American tragedy to depict the harsh landscape of the West in the 1800s.

The six-episode limited series, released Thursday, focuses on the clashes between Native Americans, Mormons, settlers moving West, and the U.S. government through the lens of two people experiencing the conflicts in real time: Sara (Betty Gilpin), a mother going West with her son, and Isaac (Taylor Kitsch), a mountain man who grew up among the Shoshone tribe who's tasked with transporting her there safely.

While Sara and Isaac are fictional characters, many of the events in "American Primeval" are rooted in history. Case in point: the first episode's bloody massacre is a dramatization of a real incident that occurred in Utah.

The Mountain Meadows Massacre of 1857 claimed the lives of 120 men, women, and children in southern Utah

In September 1857, emigrants traveling from Arkansas to California were attacked and murdered on a wagon trail by about 50 or 60 local Mormon militiamen with assistance from Paiute Indians in Mountain Meadows, Utah. Seventeen children who were 6 years old or younger were spared.

The Mountain Meadows Massacre stemmed from a feud between the Latter-day Saints (more commonly referred to as Mormons) and the American government that was later known as the Utah War.

The Mormons, led by Brigham Young, feared that they would be attacked by US troops and driven off the land, so they created their own army called the Nauvoo Legion.

Despite multiple people being involved in the massacre and subsequent cover-up, John Doyle Lee, a militia major, was the only person who faced severe punishment.

Lee and Isaac Haight, who was also involved in the tragedy, were excommunicated from the church in 1870. Lee was later convicted and executed for his involvement in the massacre. He was sentenced to death by firing squad and executed at the massacre site in 1877.

In 'American Primeval,' the massacre is the inciting incident that drives the plot

In the first episode, Gilpin's character Sara Rowell scrambles to protect herself and her son Devin (Preston Mota) when the group they're traveling with is attacked by Mormon soldiers disguised as Native Americans. Sara and Devin are about to be killed, but they're saved by Isaac, who hides them in the woods and helps them get away on horseback.

The brutality of the scene, which also depicts a man getting partially scalped, sets the stage for the rest of the season, and is a key part of the season's narrative.

"The Mountain Meadows Massacre did happen … and it became, for our narrative purposes, an inciting incident of conflict for our cast of characters," executive producer Eric Newman told Tudum, Netflix's editorial site.

Sara, Devin, and Isaac are doggedly pursued by the Mormon soldiers who want to cover up their part in the attack.

"It was driven by the Nauvoo Legion, but we have to understand that they perceived it as a threat," writer and executive producer Mark L. Smith added. "They were coming in to defend their world. It is just another step — a very violent step — in the lengths that they went to."

"American Primeval" is now streaming on Netflix.