In this episode, Veronica resolves the mystery of her sexual assault a year earlier by talking to previous acquaintances and learning about the details of what happened at Shelly Pomroy's party a year earlier while she was under the influence of GHB. Meanwhile, Duncan returns from running away earlier, and Veronica and Logan's relationship matures as she reacts to the news that he had roofies the night of the party.
Although the first season primarily deals with the murder of Veronica's best friend, Lilly Kane, and the murder is resolved in "Leave It to Beaver", another arc running throughout the season is the story of Veronica's mysterious rape a year earlier. At that time, Veronica went to a party at a wealthy student, Shelly's, house. There, she was slipped a mysterious drink, and the next thing she knew, she woke up in an unidentified bed missing her underwear", indicating that she had been raped. The next day, she walked into the sheriff's department and reported the crime, where Sheriff Don Lamb mocked her predicament and refused to conduct an investigation, leaving Veronica in tears
The episode opens in Havana, Cuba. Keith surprises a now-bearded Duncan, who denies killing Lilly. At school, Veronica avoids Logan, but that night, Logan shows up at Veronica's door. Logan apologizes for owning GHB before Veronica informs him about her rape. Logan denies being her rapist, but Veronica says she'll punish whoever it is, even if it's Logan. Veronica talks to Meg about the party, and she mentions seeing Veronica being harassed by some boys before she left. Keith returns Duncan to the Kanes before threatening Clarence Wiedman. Veronica approaches Luke about a trip to Tijuana to pick up some GHB; he admits getting the drugs, but he says that he gave them to Dick Casablancas. Luke states that Madison Sinclair was seen writing "slut" on Veronica's car after the party. Veronica confronts Madison, who says that she defaced Veronica's car because she made out with Dick, her boyfriend. However, Veronica doesn't remember this incident due to the effects of the drugs. Veronica attempts to barge in on a fight between Keith and Alicia Fennel over Wallace's involvement in the Wiedman case, but her intervention does nothing to defuse the situation. Veronica talks to Casey, who confirms the make out sessions with Dick and Cassidy, and Veronica was also forced to make out with Shelly Pomroy for the boys' amusement.
Veronica talks to Sean Friedrich and tells him about the girl-on-girl event and that Dick and Beaver took her over to a bed and argued about who should have sex with her. Veronica talks to Dick, who presents a different account of events, saying that he didn't drug her and that he found Beaver with Veronica already. Veronica approaches Beaver, who gives a set of events more similar to that of Sean. However, after Dick and Sean leave, he purports to have run away and vomited before he could bring himself to rape her. Keith says that he has to leave for an engagement in Vegas. Logan talks to Aaron, but Aaron does not even know Logan's birth date. Veronica talks to Carrie Bishop, who says that she saw Veronica having sex with Duncan. Veronica confronts Duncan, who denies the rape accusations and remembers comforting Veronica in her drugged state. Duncan says that the sex was consensual even though he knew that they were siblings, confirming Veronica's fears. Veronica talks to Wallace about the events but says that she is content with the answers she has. Keith calls a prostitute in Vegas for an unknown reason, while Veronica apologizes to Logan and tells her about the situation with Duncan. Back in Vegas, Keith talks to the prostitute, Cheyenne, about Abel Koontz, as Cheyenne and Koontz were together at the time of Lilly's murder. Veronica and Logan go into his darkened house before they realize that Aaron throws a surprise party for him, meaning that virtually the entire high school knows that they are dating.
Duncan abruptly exits the now-awkward party. Madison gives Veronica a cocktail, which she calls "A Trip to the Dentist." Noticing that something is strange, Veronica talks to Madison, who says that she spit in her own drugged drunk before unknowingly giving it to Veronica. Duncan suddenly starts smashing his car before Meg comes out and talks to Duncan, criticizing him. Logan and Veronica are making out before Logan reveals an important piece of information—that he drugged Duncan, not knowing what was going to happen between them. Logan temporarily leaves Veronica before she notices a camera in the ceiling. She investigates further and finds a whole network of cameras, hinting that Logan was using them for some nefarious purpose. She calls Weevil to pick her up before she enters the house, finding her mother with Keith.
- Logan and Luke Haldeman got GHB (also known as "Liquid X") from Mexico and brought it to Shelly Pomroy's party. Luke lent some to Dick Casablancas who wanted to use it on his girlfriend Madison Sinclair. He drugged her drink, but she, seeing Veronica, spat in it and surreptitiously handed it to her (the "trip to the dentist" of the title). Veronica ingested the drug from the drink, and Dick brought her upstairs so Beaver could take advantage of her in her unconscious state. Logan decided to create a salt lick when Veronica passed out, but Duncan stopped them. However, his drink had been drugged with GHB by Logan to loosen him up and Duncan tells Veronica that he woke up next to her, knowing they'd had sex while in their drugged state.
- Duncan left Veronica alone the next morning because his mother, Celeste Kane, had told him she was his sister.
- Keith goes to Las Vegas to talk to a prostitute who was with Abel Koontz at the time of Lilly's murder.
- Everyone finds that Logan and Veronica are a couple.
- Keith finds Duncan in Cuba.
- After a lengthy investigation, Veronica concludes that she and Duncan had consensual sex when they were both drugged.
- The Kanes believe that Veronica is Duncan's sister, and Keith learns that Abel Koontz couldn't have killed Lilly.
- Veronica goes public with her relationship with Logan before finding a series of cameras in his bedroom.
- Kristen Bell as Veronica Mars
- Percy Daggs III as Wallace Fennel
- Teddy Dunn as Duncan Kane
- Jason Dohring as Logan Echolls
- Francis Capra as Eli "Weevil" Navarro
- Enrico Colantoni as Keith Mars
- Jonathan Bennett as Casey Gant
- Alona Tal as Meg Manning
- Corinne Bohrer as Lianne Mars
- Lisa Thornhill as Celeste Kane
- Christopher B. Duncan as Clarence Wiedman
- Sam Huntington as Luke
- Kevin Sheridan as Sean Friedrich
- Erica Gimpel as Alicia Fennel
- Leighton Meester as Carrie Bishop
- Kyle Gallner as Cassidy Casablancas
- Ryan Hansen as Dick Casablancas
- Daniel Bess as Cole
- Jennifer Gareis as Deborah Collins
- Harry Hamlin as Aaron Echolls
- "Creation" - Atash
- "Kingdom of Chemicals" - Sean Dailey
- "The Other Side" - BoDeans
- "This Is Not a Game" - B.A.S.K.O.
- "I Touch Myself" - Saucy Monky
- "I Like That" - Houston with Chingy and Nate Dogg
- "Cemetery Party" - Air
- "Give You More" - Taxi Doll
- This episode was originally called "Up on the Roofie".
- This episode has the return of possibly the most (heretofore) one-shot characters in the show: Casey Gant from "Drinking the Kool-Aid", Luke Haldeman from "You Think You Know Somebody", Sean Friedrich from "An Echolls Family Christmas", Carrie Bishop from "Mars vs. Mars", and Cole from "Like a Virgin".
- Veronica: Remember when I saved you from drug dealers and I said I may call upon you for a favor someday?
- Luke: You didn't say that.
- Veronica: It was implied.
- Veronica: You wrote "slut" on my car last year at Shelly's party. Why?
- Madison: Because "whore" had too many letters.
- Veronica: So Shelly Pomroy and I were thinking of getting together later for a little girl-on-girl, you wanna come with? Wow. You know, when you're about to soil yourself, you get a little twitch right in your eye.
- Veronica: It's kinda a bad time.
- Logan: Okay, so I should come back when, never? Would that work for you?
- Logan: We were just going to have some fun.
- Veronica: Fun, like sex with unconscious people fun?
- Veronica: [voiceover] As a rule people who don't like you most likely won't help you. There were 100 people at Shelly's party. 98 of them would walk over my corpse for a piece of free gum.
- Veronica: I just learned that the dream I had where you and I were in a bedroom alone was reality. Care to share some details, lover?
- Cassidy: Nothing happened.