Background and details of plot
At the beginning of the series, Veronica is a 17-year-old Junior at Neptune High in her hometown of Neptune, California. Although she is quite witty, she is also cynical for her age. She works for her father, private detective Keith Mars, the former Sheriff of Balboa County, California. She does not have any friends until she meets and helps Wallace Fennel, who quickly becomes her best friend. A year earlier, Veronica led a carefree life as one of the popular teens at Neptune High. Her best friend was popular senior Lilly Kane, and she was dating Lilly's brother, Duncan Kane. Along with Lilly's boyfriend Logan Echolls, the four were at the forefront of the school's wealthy and popular "09er" clique (named after the 90909 zip code, a wealthy area of Neptune) that ruled Neptune High's social scene. Though Veronica did not meet the economic status of the other 09ers, she was accepted into the clique because she was dating Duncan, and her father's influence as Sheriff. However, this carefree world would not last for Veronica. One day, out of the blue, Duncan stopped talking to Veronica; Lilly was caught between her best friend and her brother and eventually became the bearer of bad news. Soon after Veronica and Duncan's breakup, Lilly was found dead at the side of her family's pool. Sheriff Keith Mars accused Lilly's father, software mogul Jake Kane, of the murder. The citizens of Neptune were horrified and Keith quickly found himself voted out of office and turned into a pariah by the wealthy 09er community. Keith's credibility took another blow when his replacement as Sheriff, former Deputy Sheriff Don Lamb, arrested disgruntled former Kane employee Abel Koontz, who confessed to Lilly's murder. The shock and loss of income destroyed the Mars family; Veronica's mother abandoned the family several months later. Veronica further sealed her fate as an outsider when she refused to denounce her father. Logan stopped speaking to Veronica, and the rest of the 09ers followed suit. Veronica found herself banished from the exclusive 09er social scene and all of her former friends. Two months after Lilly's death, Veronica crashed an 09er party to prove to her former friends that she did not care what they said about her. At the party, Veronica is handed a drink which she later finds out is a "rum, coke, and roofie." The next morning, Veronica woke up without any recollection of the night before; she realized she had been raped when she found her underwear on the floor. When she reported the crime to Sheriff Lamb, he called her a liar and threw her out of his office. Veronica later discovers that her drink laced with GHB had been meant for Veronica's longtime enemy, Madison Sinclair; Madison had spat in her drink and handed it to Veronica as a prank. Veronica believes that Duncan had raped her, but discovers that Duncan had also been drugged with GHB, and that she had consented while under GHB's influence. At the end of Season Two, Veronica puts more pieces together: Cassidy "Beaver" Casablancas had actually raped her that same night, and gave her chlamydia. These events left Veronica changed forever; she became a cynic, filled with contempt and disgust towards her classmates and Neptune's wealthy elite. A pariah like her father, she funneled her time and energy into helping her father in his own detective agency. But when a chance encounter with a new transfer student Wallace Fennel led to her gaining a new friend, she began to use her investigation talents and energy to help her fellow students and to go head to head with her former friends and their corrupt ways. Veronica slowly begins to outgrow her cynicism, with the help of new friends like Wallace Fennel, Cindy "Mac" Mackenzie, Meg Manning, and Stosh "Piz" Piznarski, whom she meets while attending Hearst College (season 3). Veronica begins to accept that everyone is not out to get her. However, when a video of her and Piz in a compromising situation is sent around Hearst's campus, it becomes apparent that Veronica's Biblical sense of justice is still intact.

Detective
Since her dad became a private investigator after being outsed from the Sheriff's Department, Veronica has had an after-school job as a secretary at Mars Investigations, her father's PI business. Though she is often forbidden to handle certain cases, she often oversteps her boundaries and sometimes even completely solves the case before her father. On top of that, she is the small-time private investigator for Neptune High: tracking down computer crackers, digging up dirt on parents, finding out who stole the school's mascot, and the like. She keeps one step ahead of her father and Vice-Principal Clemmons through the occasional help of her best friend Wallace – Watson to her Holmes – and classmate Eli “Weevil” Navarro, the leader of the PCH Biker Gang. While Veronica's activities have put her at odds with the 09er social clique, it has helped Veronica make new friends and allies at Neptune High. She has also undeniably committed many illegal and duplicitous acts in the course of doing her detective work, leading many to openly question the moral consequences of her vendetta against the Neptune High status quo. Logan Echolls (Jason Dohring), once a close friend, had helped organize the blacklisting of Veronica from the 09er clique. The two crossed swords on several occasions before Logan sought Veronica's help in finding out if his mother, Lynn Echolls, might have faked her death when she jumped into the ocean. Still reeling from the abandonment of her own mother shortly after Lilly's death, Veronica empathized with Logan's pain, and the two reconciled most of their differences. Toward the close of the third season of the series, Veronica successfully completes her California state examination to receive official licensure as a detective in her own right, though her score on the exam is slightly lower than her father's score had been.

Cindy "Mac" Mackenzie
Mac is a fictional character on The CW television series Veronica Mars, portrayed by Tina Majorino. She was a recurring character during the first two seasons, and was promoted to series regular status for the third season. Mac uses her computer hacking and cracking skills to help Veronica with her cases; the two joke that she is a kind of Q to Veronica's James Bond. Whether coincidentally or not, Mac (a common nickname for "Mackenzie") has also shown a decided preference for Apple Macintosh computers, which share her nickname.

Background
Mac is 19, a Sagittarius and her hometown is Neptune, California.[1] True to the show's spirit of moral grey areas, in the episode where Mac is introduced, she helps Veronica find out who has stolen her password and has created a false score under her name on a purity test that had become a brief fad at Neptune High. The moral ambiguity of the show is best shown in the fact that Mac, although a friend of Veronica's, is the person who created the test in the first place, thus making it possible for the "sex crazed 09ers" to access other people's purity tests - and thus is also responsible for the chaos which is the focus of this episode. Like Veronica, Mac uses an Apple PowerBook and in season three, a MacBook Pro. Mac vehemently defends the Mac OS X operating system (in the episode "Weapons of Class Destruction") in an argument with an Ubuntu Linux fan. Mac has always felt she did not belong in her family; Veronica discovers that Mac was switched at birth with Madison Sinclair. Since the mistake was uncovered four years after the births, the parents decided to keep the children. Each family received a handsome cash settlement from the hospital. While Madison's family invested and flourished, Mac's started a business and went bankrupt. She formerly dated Cassidy Casablancas, but the relationship ends when Cassidy balks at becoming sexually intimate with Mac. They are back together in time for graduation in "Not Pictured"; in the same episode, however, Veronica discovers that Cassidy had been responsible for (among other things) the bus crash that occurred in "Normal Is the Watchword". Cassidy, intercepting Veronica's message, robs and abandons Mac while she is in the shower, leaving her without clothes. He then attempts to kill Veronica, and, later that night, commits suicide. Mac attends Hearst College along with Veronica, and she initially is uncomfortable with male attention. A series of rapes on campus bring up bad memories, but she is eventually able to move on and have successful relationships.