Radio host Erica Bain (Jodie Foster) is working and living a wonderful life in New York City without a care in the world. One night she and her fiancé, David (Naveen Andrews), are brutally attacked by three thugs in the park while being recorded by one of them. David is killed and Erica is beaten within an inch of her life. Erica is traumatized to a point where she can not sleep and will not leave her apartment. To cope and work past this tragic event, Erica becomes someone else. She buys a gun and begins to roam the streets at night looking to take her revenge on the men who were responsible for killing her one true love. One late night, Erica is in the back of a convenience store about to purchase a soft drink when a man comes in and shoots the clerk, who is his estranged wife. He realises Erica is a witness and comes after her but she shoots him and escapes, taking the store CCTV video with her to hide her involvement. Days later, Erica is on the subway when she witnesses an attack on a youth by two men. They steal his iPod, and when an old man intervenes they threaten him and his son. The three of them hastily leave the train at the next stop and the two men approach Erica as she is the only other person in the carriage. They pull a knife on her but she shoots them both and quickly leaves. The City of New York is fascinated with the exploits of this vigilante killer, and NYPD Detective Mercer (Terrence Howard) is assigned to catch this person, who they believe is a man, before he kills again. Erica interviews Mercer as part of her radio show and they become friends, both linked by their inability to sleep at night. He tells her that he is prepared to go beyond the law to catch some criminals, but asks Erica to erase this comment from her tape. Erica continues to kill, rescuing a drugged prostitute from a car but, in killing the driver as he tries to run them over, the prostitute breaks her leg and when the police arrive, take her to hospital, though she is very close to death. Later on Erica gets a lead of where she can find the three men in the park and goes there to seek vengeance. She manages to kill all but the last one, being then saved by Detective Mercer whom she had already befriended and let her kill the last thug using the Mercer's gun so no one would link her to the killings.
What does Erica buy after her fiance is killed?
A gun