Juliette Ferrars thought she'd won. She took over Sector 45, was named the new Supreme Commander, and now has Warner by her side. But she's still the girl with the ability to kill with a single touch—and now she's got the whole world in the palm of her hand. When tragedy hits, who will she become? Will she be able to control the power she wields and use it for good?
Once the adrenaline of overthrowing the Reestablishment fades, Juliette becomes overwhelmed with the responsibilities of being Supreme Commander of North America. Knowing nothing about politics, she struggles to maintain diplomatic relations and is suspicious at the lack of responses from other Supreme Commanders she's reached out to. The only reply she recieves is from Oceania: a brief, informal note stating "Can't wait to see you."
Meanwhile, Warner struggles with the death of his father. Feeling ashamed of his grief for the tyrannical monster, he hides it from Juliette, which causes some tension between them. To his surprise, Adam reaches out, and the two bond over their complicated grief and the abuse they both suffered from their father.
Though still very much in love, Warner and Juliette grow distant from each other. Warner withholds crucial information from Juliette about the inner workings of the Reestablishment, claiming she doesn't need his help because she's capable of handling the job on her own. Meanwhile, Juliette's insecurities cause her to lash out and stubbornly disregard Castle's advice. She becomes frustrated that Warner never shares anything with her and that she knows little about his early life. Warner does not share these details not only because he's extremely private, but also because he's afraid she won't love him anymore if he knew the horrible things his father made him do when he was younger.
When out for a walk one day, Juliette is shot several times by an unidentified assailant. Warner frantically rushes to the medical wing to help Sonya and Sara heal her. While Juliette is recovering, Warner has a heated discussion with Castle about recent revelations of Juliette's origins and the potential threat the other Supreme Commanders pose. Warner is afraid that Juliette will hate him if he reveals the truth, but is convinced by Castle that she needs to hear it from him.
Finally, Warner sits Juliette down and reveals that the people that raised her were her adoptive parents, and that her biological parents gave her up to the Reestablishment when she was five years old. When she was adopted, her memory was erased and she was given the name Juliette Ferrars. Her sister, Emmeline, was also given to the Reestablishment, and was placed in a laboratory for study.
From her new home in Sector 45, Juliette was monitored for signs of supernatural abilities. The Reestablishment's goal was to study the people they called Unnaturals, weed out the less useful ones, and use the powerful ones as weapons to gain political power. Warner's father, Paris Anderson, was part of this plan, and had intended for Warner to find Juliette and release her from the asylum so she could become useful to their cause.
When Warner was sixteen, Anderson recieved the opportunity to become Supreme Commander of North America, which meant he would move away from Sector 45 and abandon his sick, incapacitated wife. Warner begged his father to let him be Chief Commander and Regent so he could stay at Sector 45 and keep taking care of his mother. Anderson agreed to give him the position only if he took the temporary job of overseeing the torturous experiments done on Emmeline. Warner, who was unaware of the wider conspiracy at the time, did as his father said, despite Emmeline's pleas for mercy.
Feeling sickened, hurt, and betrayed, Juliette declares she can never trust Warner again and runs away from him. Distraught, Warner has a panic attack and is rescued by Kenji, who retrieves medicine for him. Juliette moves out of the room she shared with Warner and into Anderson's old quarters, where she finds a cabinet of alcoholic beverages. She gets drunk and cuts her hair in an act of self-destruction. Warner and Kenji find her sitting in her underwear, holding a glass of whisky. Warner takes care of her and tucks her into bed while Kenji retrieves water, coffee, and aspirin. Juliette tries to seduce Warner, who gently refuses due to her inebriated state.
Juliette wakes up the next morning with a renewed sense of purpose. She meets with the children of the other Supreme Commanders and addresses them formally, with confidence she didn't have before. She ignores Warner's attempts at reconciliation, choosing to stay focused on her speech for a symposium with all 554 Chief Commanders and Regents of North America.
Several of Juliette's Omega Point friends accompany her to the symposium to lend their support. She takes her place onstage and has barely begun her speech when the audience starts heckling and threatening her. Then they draw their guns and begin shooting at her and her friends. Warner and Kenji are about to pull Juliette off stage when she starts screaming, channelling her lethal Energy at the crowd and accidentally killing all 554 of them.
Dazed, Juliette barely has time to register what has happened when she hears explosions and her body is paralyzed by a sudden electric current. Her Omega Point friends are dead, Kenji is being dragged away, Castle unconscious and Warner is placed in handcuffs. Just before she loses consciousness, Juliette sees two people who claim to be her parents and have come to take her home.
Juliette wakes up in a child's bedroom. She figures out from a collection of photos and letters that she's in Glenorchy New Zealand, and that her real mother, Evie Sommers, is the Supreme Commander of Oceania. The door opens and her mother greets her, calling her Ella. Juliette passes out from shock and exhaustion.