The narrative of American Primeval's inaugural episode unfolds in the Utah Territory, the year 1857, where a chaotic tapestry of conflict intertwines among the US Army, Mormon militias, Native Americans, and pioneer settlers. Sara Rowell, accompanied by her son Devin, embarks on a journey filled with anticipation, bound for Crooks Spring in Utah to reunite with her husband, gleefully escaping the confines of Philadelphia.
Their path crosses with John Frye, a temperamental individual who leads them to Fort Bridger,Wyoming, in hopes of securing Beckworth as their guide. Fort Bridger stands as a desolate, frigid oasis, a stark contrast to their Philly origins. Amidst this bleakness, a Native American girl brazenly snatches a knife, prompting a chase by some pioneer dwellers. Upon their arrival, they're met with the dismaying news of Beckworth's absence.
The serene atmosphere of the fort is shattered when a Frenchman, involved in a heated altercation with John, loses his temper and takes John's life. Swift justice is meted out, resulting in the Frenchman's demise. Jim Bridger, the fortress's proprietor, endeavors to persuade Sara of the perilousness of continuing their journey, highlighting the daunting task of traversing the Wasatch Mountains during the harsh winter months. Routes alternative to this perilous path are equally treacherous, with Native tribes, Mormons, or marauding outlaws posing a constant threat. The underlying tensions escalate as Brigham Young seeks to entrench Utah as a Mormon stronghold, while President Buchanan aims to thwart his ambitions.
Despite these ominous circumstances, Sara remains steadfast in her resolve, seeking a reliable guide. Jim Bridger, recognizing her determination, introduces her to Isaac Reed, a reclusive figure deeply entrenched in Native American customs and knowledgeable about the territory. Sara, driven by desperation, offers an unprecedented fee of $750, yet Isaac refuses, feigning that Devin's disabled leg could hinder their progress. Devin, bridling at the suggestion of his impairment, asserts his capability and urges Sara to cease her pleas.
Returning to the town, a group of traveling Mormons halted to procure provisions. The pioneers, though rough-hewn, were led by Jacob, who bore their insolence with equanimity. His spouse, Abish, however, lacked such forbearance. Nearby, Sara scolded Devin for his tone, and it seemed he perceived a reflection of his unwelcomed father in Isaac. He favored Jim, whereas Sara strove to integrate into Jacob's group, which initially rejected her. With Abish's covert encouragement and Sara's insistence that they possessed their own sustenance, Jacob relented. Sara thanked Abish, but she responded that women lacked influence, which was precisely why they married. Sara appeared startled yet inclined to concur.
That eve, an intoxicated Native American attempted to violate the young girl from earlier, as her mother tried vainly to intervene. The girl, driven by desperation, stabbed him and fled, unaware that he held a prominent position within his tribe.
The following morning, Jim and Isaac watched the Mormon contingent depart. Isaac deemed Sara ruthless for jeopardizing her son's life and hinted that once they were gone, he could trade their supplies. Meanwhile, Devin draped a blanket over his shoulder and discovered the girl concealed within the wagon. She was terrified, and he vowed to keep her hidden. The Mormons joined Fancher's caravan, which promised security for the remainder of their journey. Abish pondered her purpose, to which Jacob replied that their purpose was each other.
Back at Fort Bridger, a bounty hunter arrived, seeking Sara Holloway for murder and robbery, with a reward of $1,500. She hailed from Philadelphia, accompanied by a young boy, and had encountered a man named John Frye. Virgil, the outlaw who had been casting covetous glances at Sara since her arrival, was intrigued. Jim came to her defense, as her motive remained unknown.
Meanwhile, the Mormon militia emerges at Fancher's encampment, asserting their territorial claim and demanding a permit for Fancher's group to proceed. Fancher's men, brandishing an arsenal superior to theirs, summarily dismiss the militia, leaving them dissatisfied and seething with resentment. It is amidst this tense standoff that Fancher leverages Jacob's group as a security deposit, ensuring his own leverage.
As the story unfolds, Jacob reveals his unwavering allegiance to Brigham Young's self-appointed governorship over Mormon Utah. Small talk blossoms between Sara and Jacob, who confides that he had intended to wed Abish's sister, Eden, before her untimely demise. Abish, feeling like an outsider, expresses skepticism towards the blind faith of the Mormons. Meanwhile, Devin, compassionate as ever, sneaks food for the Native American girl, showcasing his hidden kindness.
Suddenly, the peace is shattered by an unholy alliance of outlaws and Paiute warriors. In the chaos, Jacob is brutally scalped, while the Native girl flees into the wilderness. Sara and Devin, seeking an escape, find themselves in a perilous situation until Isaac, who has been observing them discreetly, intervenes and dispatches their assailant. They flee the scene, leaving the outraged outlaw leader fuming in their wake. He offers a bounty to the Paiutes to track and capture the trio.
After the wagons are ransacked and left in disarray, the outlaws demand the death of the Mormon women, fearing their testimony, while the Paiute chief covets them for his own purposes. The outlaws insist on terminating the women's lives once the Paiutes have finished with them.
Elsewhere, Isaac maintains his charming yet gruff demeanor but shares his provisions with Sara and Devin as they rest for the night, a gesture that warms their hearts amidst the harshness of their journey. Meanwhile, in town, Virgil and his men murder a bounty hunter to claim Sara and the bounty themselves. One of Virgil's men expresses remorse for the bounty hunter's death, hinting at a softer side beneath their ruthless exterior.
The first episode of American Primeval concludes with a harrowing scene: the Paiutes scavenging among the dead, where one of them discovers Jacob, still alive but gravely injured. Desperate and desolate, he searches for Abish, who has vanished into the abyss of the untamed frontier.
