Nine years after the events of the show's third season, former teenage sleuth Veronica Mars (Kristen Bell) has left the fictional town of Neptune, California and moved to New York City, where she is in a stable relationship with Stosh "Piz" Piznarski (Chris Lowell) and has a job offer from the prestigious law firm Truman-Mann and Associates. She is contacted by her ex-boyfriend Logan Echolls (Jason Dohring), now a Lieutenant in the United States Navy, who has been accused of murdering his girlfriend Carrie Bishop (Andrea Estella), a fellow Neptune High student who became a successful but self-destructive pop star under the stage name "Bonnie DeVille". He is being bombarded for offers of representation from lawyers, and Veronica agrees to return to Neptune and help Logan find one who will best represent him. She is reunited with her father Keith Mars (Enrico Colantoni), Neptune's former sheriff-turned-private investigator, who shows her how corruption and class discrimination is rife under Sheriff Dan Lamb.Despite her claims that her stay will be brief and she will not get involved, Veronica begins to investigate the circumstances of Carrie's death. During her investigation, Veronica is dragged to her ten year high school reunion by friends Wallace Fennell (Percy Daggs III) and Cindy "Mac" MacKenzie (Tina Majorino). There, she learns that former outlaw biker Eli "Weevil" Navarro (Francis Capra) is now a reformed family man. During the reunion, Veronica realizes Carrie's murder is connected to the death of Carrie's best friend, Susan Knight, who disappeared off a boat at sea nine years earlier. She also sees a connection between Carrie's death & her latest album, released just a few weeks earlier, called "confessional", where she is raked with guilt. She also got a new tattoo before her death, which was the name of the boat which Carrie and Susan went on, where Susan disappeared.After Veronica's nemesis Madison Sinclair (Amanda Noret) plays a copy of Veronica's college sex tape with Piz, a fight breaks out. The reunion comes to an abrupt end as Veronica sets the sprinklers off, with Veronica punching out Madison after Madison verbally harasses Veronica further. Veronica attends an after party and speaks with Dick Casablancas (Ryan Hansen), Luke Haldeman (Sam Huntington) and his fiance Gia Goodman (Krysten Ritter), and Stu "Cobb" Cobbler (Martin Starr), all of whom were with Susan (Christine Lakin) and Carrie on the boat the night Susan disappeared. Meanwhile, while driving home from the reunion, Weevil stops to help a driver being harassed by bikers, only to be shot by the driver, a nervous Celeste Kane. The sheriff's department plants a gun so that Celeste can claim self-defense, and Keith agrees to prove Weevil's innocence.Veronica concludes that those on Susan's boat nine years ago covered up the circumstances of her death, and that someone killed Carrie because she threatened to confess. Compromising videos of Carrie are posted online and Veronica traces them back to Vinnie Van Lowe (Ken Marino), who has been planting spyware on celebrities and selling the footage. Veronica uses Vinnie's footage to prove Gia lured Logan out to Carrie's home the night of her murder, suggesting she and Luke killed Carrie and framed Logan. Sherrif Lamb (Jerry O'Connell) blatantly ignores her evidence and refuses to follow up, but unbeknownst to him Veronica records the conversation. Having stayed in Neptune longer than planned, Veronica calls Piz in New York to explain that she cannot return yet, and Piz breaks off their relationship. Truman-Mann rescinds their job offer, which results in an argument between Keith and Veronica about what she's doing with her life.Keith has a clandestine meeting with Deputy Sacks (Brandon Hillock) about Weevil's case, but they are attacked by an unknown driver in a truck who slams into Sacks' car, killing him and leaving Keith in critical condition. Veronica and Logan sleep together, reaffirming their relationship. Veronica sends bugged flowers to Gia's apartment and calls her, playing recordings of Carrie's voice, hoping to scare Gia into confessing to being the mastermind behind Carrie's death. Gia panics and calls Cobb, revealing his involvement.Veronica goes to Gia's apartment to confront her, where Gia reveals that Cobb is the mastermind of Carrie's death and framing Logan: Susan overdosed, and he took photos of a panicked Carrie, Gia, and Luke dumping Susan's body and has been blackmailing them ever since, though Carrie had recently threatened to come clean. Veronica's bug broadcasts everything via a radio frequency which she believed to be unused, but which is actually that of a local radio station. Cobb hears their conversation over the radio from his apartment in the building opposite, then shoots and kills Gia through the window before coming after Veronica. She calls the police and lures Cobb down to the basement before beating him unconscious with a golf club.Logan returns to active duty in the Navy, but promises to come back to Veronica. Cobb's photo and the secret recording of Lamb refusing to investigate Veronica's claims leak online, forcing Lamb to arrest Cobb, with calls to oust Lamb from office. Both Keith and Weevil recover from their injuries, but Weevil returns to the criminal lifestyle he left behind. Veronica takes over her father's private investigator business with Mac as her assistant, resolved to help fight Neptune's corruption.