Sabrina Galloway is a mysterious new girl in Sam's life. When Sam and Evan awoke one day, Evan's esper sense detected a battle between 1337 and the espers. He took Sam to check it out, and accessed his old esper powers and defended a powerless sam. However, they became separated, and Sabrina encountered Sam, who believed her to be an Esper. Sabrina attempted to entice the confused Sam, and saved Sam from a gunshot. Sabrina took Sam out of the ensuing chaos that spread from infected civillians entering the battle, and Sabrina drugged Sam to sleep. When Sam woke up, she was in an appartment with Sabrina in Manhattan.
Sabrina successfully enticed Sam to have sex with her. She even convinced Sam to fall deeply in love with her. After they mated, Sabrina asked Sam if she would come stay and live with her. Sam accepted as long as they could take Evan, which Sabrina allowed. Sabrina then watched as her vaginal fluids took effect in Sam's body, augmenting her abilities even further.
When Sam questioned her new power, Sabrina explained how she was given similar power from a man named Alex Mercer, and she had him to thank. She promised Sam she would take her to visit him the next day as they slept.
Over the course of the next few days, Sabrina introduced Sam to Alex and others like her, their purpose, and how to access more of this power. Their mission is to combat Genteck and the military, as they had released the virus on manhattan. In order to escape the city, they must destroy them first. Also, Sabrina has taken Sam out on some small missions to fight infected and gain power, all of which Sam showed was successful. Every night since the first night, Sam and Sabrina have slept together, engaging in sexual intercourse each night, with Sabrina using her infected power to augment Sam's own abilities and make the excitement increase.
Eventually, they conquered one of the infected lairs in the Yellow zone, adopting it into their own little hive; they then mated several times after this, the last of these was very strong, sharing powers, and eventually mutating each other to resemble one another more; they also connected more in the souls as well, essentially becoming one but separate bodies.