Episode 1 of "Unchosen" commences within the confines of a tightly-knit Christian community known as the Fellowship of the Divine, nestled in the United Kingdom. As the elders, led by Mr. Phillips, deliver their sermons during a Sunday service, families listen attentively. Post-service, the women gather to set the table for a communal meal, where all share stories and fellowship.
A young couple, Adam and Rosie, are parents to Grace, a delightful little girl with a hearing impairment. Adam's younger brother, Issac, and his wife, Hannah, are eagerly anticipating their fourth child. However, as a sudden storm descends upon the community, the adults rush back inside while the children, misinterpreting the storm as the rapture, dart about excitedly.
Unfortunately, Grace ventures into the woods during the chaos. When Rosie realizes her daughter is missing, she alerts Adam. Mr. Phillips urges Rosie to remain indoors, but she defies him and rushes into the woods to search for Grace. Adam and Issac join the search alongside the other men. In the woods, a man jumps into the river after finding Grace's leg tangled in weeds. Rosie arrives as he rescues her from the water, but he flees when Adam and Issac approach.
Rosie informs Adam that Grace's body is growing cold, prompting Issac to call an ambulance. Grace is promptly rushed to the hospital, where the doctors manage to save her. In private with Rosie and Mr. Phillips, a doctor explains Grace's injuries while they wait outside.
Reassuring Grace that everything will be alright, Rosie's mother takes her in for comfort while Hannah assists in caring for Grace. The women from the church prepare meals for the men who express gratitude for Grace's survival through prayer and thanksgiving.
Rosie, still troubled by what transpired earlier in the day, attempts to speak with Adam about it. That night, as they engage in sexual intimacy, they pray to God for more children. Rosie reflects on the mysterious man who saved Grace in the woods.
The following morning, Rosie returns to the woods to leave her necklace as a token of appreciation for the stranger. Mrs. Phillips notices Rosie's return and warns her about sin, confronting her for disobeying Mr. Phillips' orders and urging her not to venture into the woods again.
That very same day, Adam confronts Issac at their family's wood factory, scolding his brother for violating their community's rules by using a mobile phone. Issac, in a show of remorse, promises never to return to his old ways and hands over the phone to Adam. Adam, in a fit of anger, destroys the phone but raises the issue in church later that day. He tells Mr. Phillips and the rest of the congregation that Issac is a sinner, leading to the church's punishment of locking Issac in a room for reflection and repentance.
Rosie calls out Adam for turning on his own brother, reminding him that Issac's phone saved Grace's life. When Rosie demands answers, Adam cites a Bible verse that asks women to submit to their husbands. Back at the house, the man who saved Grace appears at Rosie's doorstep. Sam Devlin, the man, tells Rosie that he needs help with a wound on his hand. Rosie tends to Sam's wound and sends him away with some food.
However, Sam returns and hides inside the house. Elsewhere, Issac confronts Adam for betraying him. Adam tells Issac that if the church finds out the truth, he will be disavowed and asks him to repent in solitude.
That night, Rosie discovers Sam going through the kitchen cabinets. He takes out a knife and uses the phone to call his friend. Rosie panics and demands that he leave, but Sam reveals that he has nowhere to stay. She offers to let Sam stay in the shed. Sam thanks her and says that he is not religious like her but believes he was in the right place at the right time to save Grace. Later, Sam has flashbacks of his father praying.
That night, the church elders and Adam pray over Issac. Rosie watches Sam washing up by the shed when Adam returns home. Sam hides to avoid being seen, holding a knife for protection. He recalls killing a man at the fish factory where he worked.
A flashback shows a news channel at the hospital reporting that Sam is an absconding criminal guilty of murder as the episode comes to an end.
