While trying to navigate the everyday drama of high school, the smart, fearless, 17-year-old Veronica Mars also moonlights as an apprentice private investigator out to solve her wealthy town of Neptune's toughest mysteries. After coming to the aid of the new kid, sophomore Wallace Fennel, who's been duct-taped to the school's flagpole, Veronica ends up incurring the wrath of the thugs who put him there, Eli "Weevil" Navarro and his P.C.H. Biker Boyz. To get Weevil and his gang off her and Wallace's case, Veronica devises an intricate plan that helps some of Weevil's cronies avoid trouble with the law.

Meanwhile, defying her father, Keith Mars, the disgraced former sheriff turned private eye, Veronica pursues a late-night case of adultery against billionaire Jake Kane, only to make an unsettling discovery about her mother, who abandoned Veronica and Keith a year ago.

Veronica doesn't believe the evidence adds up against Weevil, who has confessed to stealing credit card applications from Logan's family, and launches an investigation to help her new ally.

Meanwhile, after joining Ms. Mallory Dent's newspaper class, Veronica clashes with socialite Caitlin Ford, Logan's bombshell girlfriend, but is intrigued by the attention shown to her by another wealthy student, Troy Vandegraff, a friend of ex-boyfriend Duncan. Later, Veronica learns that Lilly got a ticket driving her car on the day she died -- two hours after her supposed time of death.

With only a commonplace name, an old address and dim memories as leads, Veronica and Wallace attempt to help classmate Justin Smith find his father John, who disappeared 10 years earlier.

Meanwhile, as Veronica faces some complicated feelings towards ex-boyfriend Duncan and new romantic interest Troy, guidance counselor Rebecca James calls Keith to the school to discuss the recent, dramatic changes in his daughter's life. Later, Duncan struggles with ways to cope with his sister's death as the anniversary of her murder approaches.

In an effort to help Wallace's new crush Georgia, who was duped out of her money in an internet scheme, Veronica must outwit a group of computer "thugs," known as the Silicon Mafia.

Meanwhile, Keith makes Veronica introduce him to her new boyfriend Troy before allowing her to go to the homecoming dance with him. Later, Logan helps Duncan edit together a memorial video for a school dedication ceremony marking the one-year anniversary of Lilly's death. The dance and the video bring back Veronica's memories of when the four of them were friends.

Veronica investigates possible fraud in the election of student council president at school after Duncan wins, beating a more popular, but less affluent student who promised to eliminate the wealthy students' on-campus perks.

Meanwhile, Logan causes a public relations nightmare for his movie star parents Aaron and Lynn Echolls when footage of him organizing boxing matches between homeless men is posted on the internet and leaked to the media. Later, Veronica and Keith learn that the man who admitted to murdering Lilly is set to be executed, but a second look at crime scene photographs puts his confession in question.

When Weevil's poker winnings go missing after a game at Logan's place, Veronica questions each player to piece together the evening's events and catch the thief. Meanwhile, on the eve of the Echolls' annual Christmas party extravaganza, Keith is hired by Lynn Echolls to track down one of her husband Aaron's potential stalkers.

Following an emotional reunion with her mother, Veronica is hired to track down Neptune High's beloved mascot, Polly the Parrot, which was apparently kidnapped by a rival school on the eve of a big basketball game.

Meanwhile, with her suspicions about the Kane family rekindled, Veronica attempts to gain access to her father's original interrogation tapes. Later, Veronica's relationship with Deputy Leo heats up, as does Meg's relationship with Duncan.

Veronica investigates who at school is doing everything possible to distract Sabrina from studying and wreck her grades in an obvious attempt to sabotage her chances at becoming valedictorian.

Meanwhile, an unsavory, rival private investigator makes Keith a business offer. Later, Veronica pursues a risky lead that could discredit Abel Koontz's confession, as Logan stumbles onto her detailed files on everyone connected to Lilly's murder.

In the shocking, action-packed season finale, a determined Veronica must betray someone she cares deeply about in order to solve the season-long mystery of who murdered her best friend Lilly Kane, but what she discovers puts her life in serious danger. Meanwhile, on the eve of a reception for the Governor of Calif., Jake Kane asks Duncan if he really wants to know what happened on the night Lilly died. Later, Keith awaits the results of a paternity test.

As the end of the first semester at Hearst College draws to an end, the election for sheriff in Neptune comes to a close and Veronica and Piz discuss the effect a summer apart will have on their relationship.

Veronica and Keith follow a new lead, and discover another victim. Matty follows her own instincts, landing herself dangerously close to a killer. Veronica has a tragic epiphany as the clock is ticking.