Helena Bertinelli is the daughter of Frank Bertinelli, a high profile mobster. Some time before the show takes place, Helena, who was engaged to a man named Michael, had been negotiating with the FBI to bring her father to justice. She put all her information on a laptop, which her father found. Believing that the laptop belonged to Helena's fiancee, Frank had Michael killed. Since then, Helena has been systematically destroying her father's organization.While trying to kill a corrupt man working for her father she nearly kills Moira Queen.

Oliver tracks Helena and learns of her secret identity as an avenger with her own cause. He starts dating her in order to learn more about her motives. When she uncovers his persona as Arrow they begin a romantic affair. During their brief time together Oliver tries to change her cause, and teach her the difference between justice and revenge making her his protege. She assumes a secret identity, wearing the traditional Huntress costume, although she isn't known under that name. After learning of Oliver's interest in Laurel, believing that she was merely a plaything rather than the more serious relationship she believed they were developing, she turns against him, reveals her identity to her father, departing the city after informing Oliver not to follow her unless he wants her to reveal his identity. Oliver later states that he is sure he will see her again.

After spending some months away from the country she returns to Starling City after hearing that her father would be in witness protection rather than jail if he testify against other mobs. Helena gets the attention of the police and Oliver after killing her father's lawyer. She later contacts Oliver saying that she would need help against the U.S. Marshals protecting her father, and that if he didn't help she would hurt someone he loves, which later turns out to be Oliver's best friend Tommy. After first tracking down the transport truck for her father, Helena is captured by the police since they knew she would attack her father.

After spending some time in jail, Oliver breaks her out and gives her a new identity for her to leave the city. Instead, she steals a crossbow and threatens Oliver's computer hacker friend, Felicity, into finding out where her father's safe house is located. After Helena kills a few U.S. Marshals, Oliver finds her and they fight while her father escapes into the woods. Oliver then shoots an arrow toward Helena, and Helena reveals that while she was away she has been training to catch arrows, thus catching the arrow that was intended to kill her. As a distraction to get away from the police and Oliver Helena uses her shot gun and shoots Oliver's new girlfriend, McKenna, who is the first cop on the scene. Helena then escapes, vowing that she will not stop until her father is dead.