The character that we will know as Jessi begins life as 781228 XX.
The room with security monitors where Cyrus Reynolds reports to Rebecca Thatcher about 781227 being seen at the Zzyzx fence also contains a large tank filled with a pink liquid. After Rebecca says that she will "take care of 781227, and Adam Baylin", we see a female face for a figure lying asleep inside the tank, with "XX" (genetic code for female) as a label at that end. Rebecca tells Cyrus that "781228 is in excellent condition", and that number is the label at the other end of the tank.
When Tom Foss is in Zzyzx to "remove the threat", he enters a room and is surprised to see a gestation tank. Using the security monitors, Foss sees Kyle in a hall. Kyle is drawn to the same door, and feels the presence of someone inside that room. The agitated movement that 781228 shows when Kyle is present is similar to the agitation of the fetal 781227 when Adam was being ousted, and serves as a first spark of waking life.
Along with anyone else in the compound, 781228 would have been killed by the blast. However, the tank was sufficient protection to leave 781228 only liberated, and beginning life without Foss to help as he had with 781227. She also must resist the heat and flames to get out of the burning compound, without any of the training that Kyle later had. The healing properties of the pink amniotic fluid will be shown in Season 3; and there will be later examples of 781228 being more durable than Kyle.
She is first seen wandering through the woods, naked and wet like 781227, but sullenly in the dark rather than with his amused curiosity in daylight. Her first encounter is a hunter cooking meat at his campsite. To amuse himself while chewing, he throws his big knife into a tree trunk.
When she approaches to eat as she sees him doing, he makes advances to the naked young woman who does not speak. She continues to mimic his actions, trying to drink from his liquor bottle as he offers, but spits it out and is very distressed at being led to do something hurtful.
When he tries to touch her, she knocks him completely across the campsite with a single arm motion. Dazed and bleeding on the forehead, he is angry. He pulls the knife from the tree.
He comes towards her waving his knife, and she calmly watches how he moves. In an instant, she has the knife, and waves it towards him as he was doing. When he demands that she give him the knife, she again imitates him by throwing the knife to the same tree trunk, where it penetrates in to the handle.
When he then starts to attack her, she lifts him with one hand by his throat, much as 781227 had done with the rattlesnake, and simply watches as he stops struggling. When she releases him, he falls limp and still. Stepping over him to the fire, she eats the cooked meat.
781228 is next wandering through Juniper Park, wearing the hunter's plaid coat. Again copying, she sits down on a bench with an old man, and is fascinated by the wrinkled skin on his face. When she feels her own face and is puzzled that it is smooth, he smiles. She copies his smile. A baseball rolls to her and she tries to eat it. The boy who dropped it asks for it back, but she can only mimic his reaching out. When Kyle jogs by on the way to meet Foss, Kyle and 781228 are again aware of each other. When he stops, she sees him, but he does not see her.
She is so disturbed that she leaves, wandering to a loading dock with shipping containers. There she finds a wide-angle mirror on a forklift and sees herself, after seeing so many other people, but is puzzled by the distorted vision in the broken glass. Poking at it, she breaks the glass more and cuts her finger. Tired and confused and with some pain, she turns around and wanders among the large shipping containers.
Emily Hollander has been sent to find her, and she sees the blood and hears tapping inside a container. She finds 'XX' inside, drawing with dots the way Kyle does. 781228 is fascinated by the flashlight, and that is a distraction while Emily shoots her with a tranquilizer dart.
XX is not dead, but is out long enough for Julian Ballantine to come from Madacorp and see the drawings. They are mostly of the hunter attacking her, some of the old man on the bench, and there is a huge one of Kyle. When Julian sees it, he realizes that 'XY' was not terminated. That is the beginning of his plan that creates "Jessi".
Continue to Jessi in Season 2.