A former engineer in the Silo, Juliette Nichols is the current Sheriff of the Silo, for which she assumed the role after the previous Sheriff went "out to clean". Juliette is a skilled mechanical engineer, and has been working in the engineering department of the Silo since a young age, when she decided that she did not wish to pursue a career in medicine like her father.
Juliette becomes weary of the Silo and its operation after she begins a secret, non-sanctioned relationship with fellow resident of the Silo George Wilkins. George shows Juliette several relics and tells her that the Silo is not what they think. After he mysteriously falls to his death in the Silo one night, Juliette becomes obsessed with finding out what he knew and what happened to him. This leads her to Sheriff Holston, whom she shares George's findings with. After he opts to leave the Silo, Juliette becomes the next Sheriff on his wishes and vows to find out the secrets of the Silo.
Throughout the series
Born in the Mids, Juliette is the daughter of Doctor Pete Nichols and Hanna Nichols; she had a younger brother, Jacob, with the latter two dying when Juliette was thirteen years of age. Due to her father's busy schedule as a Doctor within the Silo, she was tasked with taking all of their belongings to be recycled.
Shortly after this, Juliette forged a letter from her father to allow her to study under Martha Walker in Mechanical. Martha was aware that the letter had been forged, and contacted Juliette's father. Juliette remained defiant, however, and cited that she wished to remain in Mechanical. After seeing her passion for the trade, Martha allowed this and she was assigned to be Knox's shadow.
Relationship with George
Juliette had a unsanctioned relationship with George Wilkins for an unspecified period of time. George introduced Juliette to his discovery in the down-deeps of the Silo, and shared with her several relics that he thought were of interest in discovering the true purpose of the Silo. The two would often frequent an undisclosed location within the Silo that housed a large drill—presumably the one used to core out the Earth in preperation for the construction of the Silo.
Following George's death, Juliette was the first resident of the Silo to acknowledge that she did not believe his death to be an accident, and that he was presumably murdered to stop him getting too close to the truth. Later, Juliette proceeded to investigate George's death and carry on his investigation into the inner workings and purpose of the Silo.
Eventually, Juliette learned that George was already in a relationship when he began his relationship with her and as a result, she felt deeply betrayed by George's actions. Juliette eventually found a video on the hard drive that George left behind in which George explained that he was originally using her to aid in his investigations, believing her to be the only one inquisitive enough to assist him. After spending time together, however, George revealed that he fell in love with Juliette
Working with Holston
After making initial contact with Holston, a flashforward shows Juliette as she reacts to the shock of Holston's apparent death after venturing outside the Silo. Angered and disbelieving, she storms off to engineering and accidentally causes a flood by damaging a pipe in her rage.
The narrative then takes us back to an unresolved issue from Juliette's past: the mysterious death of a man named George. She suspects that he was murdered and that his death had something to do with a cryptic letter and a Pez dispenser he'd meant to give her. After his death, she tells Holston her suspicions and shares the letter, which guides them to a concealed area containing remnants of an excavation robot and other artifacts.
Among the relics they discover is a bag with instructions for recovering erased files written in Allison's handwriting, along with a computer drive. Despite Holston's warnings, Juliette's curiosity is piqued. This hidden cache of items suggests a larger mystery at play, possibly related to George's death and the true nature of their world.
Holston, seeing Juliette's determination, advises her to keep a low profile while pledging to assist her in uncovering the truth. This relationship is further complicated by Holston's interest in George's connection with Allison, and he recognizes a similar fearless spirit in Juliette.
In the present timeline, Holston's final letter is revealed, endorsing Juliette as his successor and leaving her his personal belongings. This unexpected inheritance, paired with her prior suspicions, seems to cement her resolve to investigate further. The episode ends with Juliette preparing to descend down a suspended metal beam, likely following a clue related to the mysteries surrounding them.