Four New York girls, Kate, Rose, Rachel, and Claire can't recall what events happened the previous night. News spreads at the school board that the NYPD found one of the girl's body at Central Park.
The four girls are at the mercy of a man whose behavior sounds exactly like that of a rabid dog. But when Rachel displays a supernatural ability to break free from his grasp, the stranger is suddenly struck by a bus. Aghast and in shock, all four are approached by the mysterious woman who calls herself Lula, and her silent partner JC.
Lise's father questions Kate about his daughter's diary and later, the four girls attend Lise's funeral, but upon seeing Lula and JC also there, they react with upset. She gives them a red seed and instructs them to plant it if they want to know the truth...
Kate starts to befriend the other girls to help them cope with their current situation, quickly earning Rose's trust and friendship. Both decide to pay a visit to Rachel and Claire. However, the socially withdrawn Rachel disdainfully chases the two of them out of her house alleging that it is no use to resume their normal lives since all are already dead.
The girls get summoned for another fight but Rachel goes crazy and leaves. Kate and the others go after her and they learn from Lula that if one of them strays from the group they will die.
Hervé recalls his mother's death when he was a child. He goes to visit Dr. Bender to check on the health of both his sister and his cousin, but his cousin suddenly falls ill and is diagnosed with the same symptoms his mother possessed at the time of her death.
Kate, Rachel, Rose, and Claire are getting used to what remains of their so-called lives. While they may never be "normal" again, at least they can count on each other - no matter what.
Emma introduces Emilio, her fiance, to Kate. At school, Luke accuses Rachel of having an affair with the teacher, prompting her to breakdown in tears. Claire reluctantly returns to her former employer at the hamburger shop but finds out that he has truly missed her.
Hervé persuades Emilio to have Emma bring Kate for a day out with them, and later he volunteers to walk Kate home together alone. But his intentions are to get closer to Kate in order to understand his enemies.
Complications among the girls' teamwork arise during their next sleepless mission when Rose's fear to take part in the fights endangers Rachel's life. As a result, Kate finds out the hidden abilities within her new body and Rose goes to see her for training to become stronger.
Paula has a brief meeting with the school principal to discuss telling the truth to Kate, but the principal asserts that they are not to take action, but only to protect her. Later, Kate learns that Herv? lied to her the previous date, but he soon meets with her to tell her the truth.
Tormented by visions of Mireille's demise, Hervé tries to find the strength to spare Lise from the same horrific end. Kate is shocked by Hervé's revelation - and a visit from the police.
At a requested meeting late one night on the docks, Herv? discloses that she and her friends have been fighting for an organization called Animus. Ages ago, members of said organization stole one of the two Cursed Tomes which were possessed by the ancestors of Herve's clan, Dolore, casting on the latter the curse which is inherited through generations.
Kate visits the school's teacher to confirm the truth that Herv? disclosed to her, that all four of them will eventually lose all of their memories and live forever in their ageless bodies. She tells the truth to Claire, Rachel and Rose.
Hervé kidnaps Lise with Emilio's help and brings her to the sea. There, he apologizes to her and leaves. However, one of the officers, Claude, has been following them and finds Lise walking into the water. After a visit at Lise's tomb and a chat about how to live their lives in the future, the four girls decide not to fight.
Inspector Neil dials Kate to inform that he saw Lise alive but in custody of a group of men. As he is following the vehicle transporting Lise while at Brooklyn Bridge, it loses control and crashes. Meanwhile, Kate does a search on Vivaleo Pharmaceuticals and phones Herv? to demand Lise's return, but the conversation is cut when a group of Dolore men kidnaps Kate and brings her to Dr. Bender.
Hervé and Emilio infiltrate Vivaleo Pharmaceuticals as well as Lula, Rachel, Rose, and Claire. Emilio creates a commotion in the lab to help Kate and Lise escape, but Kate won't go because she deems him a liar. Herv? goes to find Anna, but she is held in custody by his grandfather, Lauro.
Christmas Eve provides the girls with a chance to enjoy one last moment with their loved ones. But when the sun rises, the time to prepare for battle will have arrived.
The bridges connecting Roosevelt Island are destroyed by a set of explosions to cut all access to the mainland. War erupts among the Animus and Dolore, as casualties arise from both sides. Hervé, with Anna in his arms, breaks into the school grounds. The four girls follow in pursuit and find Lise at the school.
