The Director reviews his file on Weapon X’s agent Marrow. He thinks that the inclusion of a former X-Man was inevitable and draws parallels between Wolverine and Marrow, which encouraged him to attempt her recruitment. The director anticipates that the main difference compared to Logan will be that Marrow’s spirit can be broken. The best way to test her new loyalties is to force her to betray someone who trusts her and who saved her life. This test will determine if Marrow’s newfound beauty is only skin deep or if she still harbors her darker rage.
While he observes his scientists working on Marrow, the Director remember how the former X-Man came to him in search of a normal body. In the past she used her bone protrusions to commit brutal acts of violence and even murder, and she would like to see them gone to become beautiful. Although the Director doesn’t understand how somebody could place the desire to be desired higher than the ability to kill with her own body, he is willing complied to make the desired modifications in return for her services. His scientists came up with the process to slow down her bone growth, and even though the operation is untested and risky, Marrow is eager to have it done. During the process the bone shards shoot out of Marrow, killing several of the medical staff, but the operation is a success. Marrow steps out of the machine and admires her new self in a reflective surface. The Director comes in and addresses admiring her as Marrow, though she says she would prefer to be called Sarah from now on.
The Director then tells Sarah that he presumes she’s ready to go out on her first mission. Sarah wants time to decide, but the Director replies that there is no time. Sarah is torn between her loyalty to the target, D’Gard, who once saved her life and her newfound beauty. The Director says that D’Gard is a mutant terrorist and that he has recently been captured by a competitive agency. Weapon X would prefer him removed from their employ. Sarah hesitates, she asks if her body will change back to it’s ugly looks, but the Director ensures her that she has his word it won’t happen.
She finally agrees, but asks for some time. The Director complies, but tells her that Mesmero and Kane will go after her if she decides to break her promise, and then she will lose more than just her newfound beauty.
Hours later, Sarah stands outside the club where she and the other members of Gene Nation once murdered a number of humans. She is feeling guilty for her actions, but her thoughts are disturbed when a man asks her if she had been inside yet. The doorman recognizes the good looking woman and calls her over, calling her beautiful, he lets her in for free. Sarah is surprised, not too long ago, the crowd would have made fun of her.
Inside Sarah is looking at all the people, but she keeps seeing the dead bodies of the people she killed – all because she wanted to fit in. Now that she is one of the normals, all she can see is the death that she caused. However she doesn’t care though, because she is now inside, accepted, happy and free. Sarah has walked towards a swimming pool and in the water she again she again sees the dead staring back at her. She tries to convince herself that her eyes are just playing tricks on her, must be the lights of the nightclub. She is convinced to no longer be that person anymore. Sarah does not notice that Kane is watching her from a nearby balcony.
A man walks up to her, concerned as she looked frightened for a moment. He introduces himself as Junichi and asks her to go swim with him in the pool. Sarah is surprised that a good looking man is smiling at her and holding her hand. She tells him her name : Mar... Sarah. Together they jump into the water, and enjoying her new life, Sarah starts to sink, but Junichi saves her from drowning. The crowd are concerned and tend to her, and Junichi says she must be getting this kind of attention all the time, though she says actually never.
Several hours later, Junichi and Sarah are in bed and Sarah comments how happy she is, she never wants this night to end. Suddenly they are interrupted by the intercom telling them that they have a visitor, a really big and mean one. Junichi says that he wasn’t expecting anyone this late, though Sarah suspects that it is someone from Weapon X, so she asks Junichi to stay in bed and goes to talk to him. Junichi asks if it is a boyfriend of her, but she assures him that it’s not and that she will handle it.
In the floor, Sarah tells Kane that she asked for some time, but he tells her that the time is up, as D‘Gard is being moved from his current position and the Director wants him out of the picture now. Sarah refuses, saying that somebody else could handle it and she would take the next job, but Kane attacks her. He grabs her by the throat, but Sarah grabs his arm and uses his own momentum to throw him out of the window. Stating that despite her looking good now, she could still rip him apart, Sarah jumps out of the window after Kane. However her actions betray her words, not yet accustomed to her new body, Sarah miscalculates and the landing is everything but graceful. Still hurting, Sarah gets sneaked up from behind, and Kane tries to strangle her with a steel cable. He taunts her that having an intimate relationship will not make her a normal woman. Sarah gets angry, she says he is the bigger freak, as he chose to look like that. She grabs a metal pipe and hits him with it, and then electrocutes him with a severed cable. Sarah intends to at least take him with her if she has to die, yet the high voltage short-circuits Kane’s bionic parts and he blacks out.
Sarah thinks she is truly free now, though she wants a life without Weapon X. She returns to Junichi and tells him that they have to run away together. Junichi tells her to relax; they have all the time in the world and ask her to join him in the shower. Sarah tells him that it‘s urgent and they have to go, but as Junichi’s eyes start to glow, she forgets her doubts and follows him into the shower. While they hug each other under the running water, Sarah repeats that they have to get away. Junichi replies that he would love to come with her, and that she is very brave. When he comments how easily she beat Kane, Sarah wonders how he would know Kane’s name. When Junichi’s skin turns green, Sarah realizes that Junichi is actually Mesmero. Mesmero tries to hypnotize Sarah, forcing her to complete her mission and to love him afterwards, but Sarah knocks him down through the shower wall. With glass shard sticking in his back, and bleeding from multiple wounds, Mesmero still tries to hypnotize her, so she uses what remains of her power to form a bone knife out of her hand. She stabs Mesmero in the throat with knife. With his last breath Mesmero tells her that he knew she couldn’t fulfill her duties, but Sarah tells him that she will prove that she can handle anything that Weapon X throw at her.
Somewhat later, Sarah makes her way to the top secret penitentiary where D’Gard is held prisoner. On her way in she kills several soldiers and finally reaches D’Gard’s cell, hiding a bone knife behind her back. At first D’Gard does not even recognize her, but then tells her how beautiful she looks. Sarah asks him to be quiet and apologizes. She then rams her knife into his gut, and as he wonders why she did it - after all he saved her life – Sarah replies that this is why she will make his death a quick one.
Hours later, Sarah sits on the Brooklyn Bridge, thinking about the recent events. With an expression of pain, she jumps and falls down into the water.
The Director‘s final notes on the mission are that the assassination was a success and that Kane and Mesmero will recover. He further thinks that Weapon X expected Sarah to go on a murderous rampage after fulfilling her duties or that she might crumble under the weight of her new self, but instead she returned to Weapon X, cold and confident, almost like a goddess.
Still wet, Sarah walks into the Director’s office. He asks her how she feels, but Sarah replies that she doesn’t feel anything. She uses a boneknife to cut off her ponytail, and throws the hair on his desk. Sarah explains that beyond being hurt anymore and desires to be called Marrow again.