Morning at the Mars apartment. Keith tells Veronica the "E-String Strangler", supposedly caught in Oakland (Keith was involved while he was sheriff), has struck again. At school later that day, Veronica and Wallace are talking about it until a kid named Jackson interrupts them:

->'''Jackson:''' I hear you do detective stuff for people.
->'''Veronica:''' I do favors for friends.
->'''Jackson:''' I can pay.
->'''Veronica:''' Sit down, friend.

Jackson wants Veronica to dig up dirt on his parents because he thinks they're being hypocritical about being strict towards him. Wallace snarks Jackson's never had to deal with the likes of his mom, but Veronica, while warning him TheSeventies and TheEighties weren't pretty times for people, agrees to help Jackson as long as he pays, of course. They're interrupted by a string quartet playing "Birthday" by Music/TheBeatles and Madison Sinclair handing out invitations to her birthday party while enjoying a birthday cake delivered to her.

Later that day, Veronica is back at Mars Investigations, looking up info on Jackson's parents, when she's interrupted by the arrival of Sheriff Lamb and the Mayor, who are both there to see Keith. Veronica is shocked by this, but Keith is expecting them and waves them into his office. Some time later, they leave and the Mayor thanks Keith. Keith then tells Veronica he's been hired back temporarily by the sheriff's department to help them find the E-String Strangler. Veronica is not only excited about the prospect of Keith working at his old job again (only because the killer is disrupting tourist revenue), but also because Keith now has access to the anonymous call that fingered Abel Koontz. However, Keith tells her that's not part of his agenda.

In the girls' bathroom the next day, Veronica tells Jackson about his parents' past misdeeds, and he's happy to hear it.

Meanwhile, at the sheriff's department, Keith and Sheriff Lamb tell the other deputies - including Leo D'Amato (Max Greenfield), a new deputy - about the E-String strangler, though of course, [[GreenEyedMonster Lamb tries to act like the bigger authority since he doesn't want Keith there.]] It's established there have been two new victims so far, and since both murders happened over the weekend, Keith guesses the killer has a Monday to Friday job.

Back at school, word has spread about Veronica's willingness to check up on parents in exchange for cash, and Veronica now has a booming business. Later, at Mars Investigations, Mac comes over and volunteers her services in helping Veronica, proposing they can get twice as much work done with her computer prowess, and make enough money for their prospective college funds. Veronica pleads overwork, but says she'll think about it. Mac then asks Veronica to look up stuff on her parents, which Veronica volunteers to do for free. She notes [[{{Foreshadowing}} Mac just had a birthday]], and that her mother won a $1 million lawsuit against Neptune Hospital. Mac doesn't understand this, because her parents hate lawyers and hospitals, and Veronica promises to look into it. At the library that night, Veronica looks through microfiche of old Neptune newspapers, and is shocked to discover the reason behind the lawsuit, which she thinks could ruin Mac's life.

The next day, at a guitar shop, Keith and Sheriff Lamb spot a band warming up. They eventually get the attention of Gabe (Steve Monroe), the lead guitarist. They ask Gabe if there's anything distinctive about the string used to strangle the women, but he snarks that it's just like any other guitar string. He and Lamb also snark at each other about feeling "inadequate" before Lamb and Keith finally leave.

Later, at Mac's house, Veronica drops by, and meets Mac's mother, who, just as Mac said, is nice, but very different from Mac. In her bedroom, Mac asks Veronica what she found out. Veronica admits what she found out is life-altering, and tells Mac to reconsider, but Mac still wants to know. Veronica tells Mac she was [[SwitchedAtBirth sent home by the hospital with the wrong parents]], which explains the lawsuit. Veronica also says another family was involved with the lawsuit, with a baby born a day after Mac. Mac takes it in, and then realizes:

->'''Mac:''' I was switched at birth with Madison Sinclair?!?

At the sheriff's department, Keith interrogates Vic, a bartender at Body Shots, where one of the victims was last seen. [[SmugSnake Vic claims he just doesn't notice "hot women" at bars anymore]], but changes his mind when he sees Veronica outside the interrogation room, and claims he would have noticed her. [[PapaWolf Keith, of course, knocks Vic out of his chair]]. Veronica, in the meantime, introduces herself to Leo, and says she has food for Keith. Leo, flirting with Veronica, says there's a fridge for the food, but tells Veronica he might be tempted to eat the food unless she stops by to visit. [[AllAccordingToPlan This suits Veronica just fine]], and she leaves with a smile on her face. Back in the interrogation room, Vic, now more cooperative, tells Keith and Lamb about a guy known as "The Worm" who videotapes the girls at the bar and sells the footage to ''Girls Gone Wild''.

Keith and Lamb visit Eddie [=LaRoche=] (Aaron Paul), alias "The Worm", at his apartment. Keith shows [=LaRoche=] a picture of one of the victims, but he claims not to recognize her. To Lamb's confusion, Keith accepts that, and lets [=LaRoche=] go by giving him his card. As they leave, Lamb points out the guitar in [=LaRoche=]'s room, but Keith points out they want to make sure he doesn't destroy his tape collection before they get a warrant.

At school that day, Veronica asks Mac how she's doing. Mac is holding an invitation to Madison's birthday party, and Veronica tells her it's a bad idea to crash the party, but Mac is determined to see how the other half lives.

That night, Mac and Veronica, along with Wallace, drop by Madison's party. Madison is horrified to see them, even after Wallace explains, "I came to celebrate your birth, but [[AllWomenAreLustful these two just wanna hook up]]." Veronica, of course, is mindful of what happened the last time she was at an [=09er=] party - though she is approached by another classmate who is willing to pay her to look up stuff on his parents - but Mac is still determined. Mac claims to want to look for a bathroom, and starts wandering around the house, eventually ending up in the rather large library. Mac notices Lauren, Madison's younger sister, who bears a close resemblance to Mac. They bond over the book Lauren is reading until Madison shows up, furious about Mac being there. Veronica shows up as well, and manages to drag Mac out of the room and the house.

Later, outside Mac's house, [[InnerMonologue Veronica notes she can't imagine how Mac feels]], [[Recap/VeronicaMarsS01E09DrinkingTheKoolAid because she herself chose not to find out the truth about who her real father is]]. Mac bitterly snarks on Madison not appreciating what she has. She also wants to know why they were never switched back; Veronica guesses each family grew attached to what they had. She also promises to find out what happened to [[{{MacGuffin}} the million dollars her family won]].

At the sheriff's the next day, Lamb finds out ''Girls Gone Wild'' never heard of [=LaRoche=], and Leo tells them the guitar string from [=LaRoche=]'s guitar matched the one used on the victims. Keith and Lamb decide [=LaRoche=] is the guy and plan to look through his tapes to see if any of the other victims are on them.

Later, at the sheriff's department, Veronica, as promised, brings pizza for Leo, [[InnerMonologue while confirming the real reason she's doing this is to continue to try and solve Lily's murder]]. Leo is joking about how he became a cop when Weevil comes by, [[BlatantLies "complaining" about the noise in his neighborhood]]. While Leo deals with this, Veronica steals Leo's key to the evidence room and takes the CD containing the anonymous phone call fingering Koontz. When she comes back, Weevil stops his complaint and leaves. Leo and Veronica go back to their pizza. He's a little thrown when he finds out Veronica is only 17 (he's 20), but he invites her to see him play in his band. She accepts.

That night, at her apartment, she listens to the CD, which contains all sorts of calls about Lily's murder, but is stopped short when she hears a distorted voice that fingers Koontz. In the living room, meanwhile, Keith is watching one of [=LaRoche=]'s tapes and sees one of the murder victims on them.

The next day, at the sheriff's, Keith tells Lamb what he saw, and Lamb says he already has [=LaRoche=] in interrogation. The two of them question a strung-out [=LaRoche=], and he says he'll tell them if he can go home. Lamb triumphantly gives [=LaRoche=] a pad and pencil, and Keith asks to speak to him outside. Once outside, Keith points out they only have circumstantial evidence on [=LaRoche=], and his apartment is too small to have kept the women captive, but Lamb blows him off. He goes back to the interrogation room, only to find [=LaRoche=] has written, "I want a lawyer."

Later, at Mars Investigations, Veronica calls Mac, telling her she e-mailed the sound file of the anonymous call, and asks Mac to take a look at it. Mac agrees, but sounds distracted, and we see she's parked outside of Madison's house. Veronica also tells her Mac's adoptive dad used to own Funtime Motors, but lost the business, which is where the million dollars went. Mac thanks Veronica, hangs up, and walks up to the house. She rings the bell, and Madison's mother, who looks a lot like Mac, answers. After they look at each other, Mac recovers, and says she thinks she left her purse there when she was at Madison's party. Mrs. Sinclair invites her in, and Lauren happily greets Mac when they come in. Lauren goes to look for Mac's purse, and Mac and Mrs. Sinclair make awkward small talk until Madison shows up, and disapproves of Mac being there. She huffs off, and Mac, though she had accepted Mrs. Sinclair's offer of a snack, thinks twice about it, and hurriedly leaves when Lauren brings back her purse.

Back at the sheriff's, a woman says her daughter has gone missing, and yells that [[MamaBear she'll hold the department responsible if her daughter ends up being a victim of the E-String Strangler]]. Keith, who was on his way out, changes his mind about leaving the case. Deputy Sachs finds out one of the victim's had the bartender's phone number written on her writs, and Lamb puts out an APB on him, while Keith tries calling Veronica on her cell phone.

Later that night, Keith continues to try and call Veronica while tracking her cellphone by its GPS signal. He pulls up outside what appears to be a decrepit-looking building, walks up to a door, and kicks it in. Inside is an embarrassed Veronica, along with Leo and his band. Keith tells them a young woman has just been kidnapped. He notices the padding around the walls, which Leo says the band put up to block out the noise, and [[EurekaMoment Keith figures the killer might have done the same thing]]. Keith asks one of the other band members to make sure Veronica gets home safely, and he and Leo go to the guitar shop he and Lamb had gone to earlier.

Outside the shop, Keith notices a wrist band from the same club the other victims went to, and heads in, telling Leo to signal him if the killer shows up. Inside the shop, Keith briefly stumbles in the dark, and a woman yells out, asking to be let out. Keith assures her he's on it, and tries to turn a light on, but ends up turning a strobe light on. He sees a small refrigerator that's padlocked, and with a crowbar he brought with him, eventually breaks the lock and gets the woman out. What he doesn't know is Gabe, the guitarist from earlier, is creeping behind him and about to hit him with a weapon, at least until Leo tackles him from behind. Gabe gets the better of Leo, but Keith pulls out his gun and holds it to Gabe's head, at which point he gives up.

At the sheriff's department, Veronica greets Leo and thanks him for saving Keith's life, but Leo tells her he's been suspended for leaving the evidence locker open and losing his key. He leaves with his stuff, and Veronica looks chastened. Mac calls her and tells her she thinks she's decoded the phone message, if she can come by the next morning before Mac leaves on her camping trip.

At Mac's house, while the [=MacKenzies=] get ready for their trip, Mac plays the recording for Veronica, and after a few tries, Veronica recognizes Clarence Wiedman's voice.

Outside the house, as Mac and her family pack up their camper, Mac notices Mrs. Sinclair parked outside. She walks up to her biological mother's car, they look at each other, and each put their hands on the driver's window as Mrs. Sinclair starts to cry. Mrs. [=MacKenzie=] yells for Mac one last time, and Mac turns away to leave.

At Kane software, Clarence Wiedman's receptionist tells him he has a package. It's a photograph of him, his young son, and Jake Kane. Clarence asks his receptionist to track down who sent the photograph to him and who took it; of course, it was Veronica.

This episode contains examples of:

* CallBack: The revelation about Clarence Wiedman taking photos of Veronica, the anonymous call about Abel Koontz, the [=09er=] party where Veronica was raped (and the invitation written in [=09er=] code), and, of course, the question of who Veronica's real father is.
** Veronica mentions Mac's beetle, bought with the profits of a website that drove the plot in "Like A Virgin". Mac admits it outright.
* ContinuitySnarl: This episode was originally supposed to air before "An Echolls' Family Christmas", but was switched around thanks to ExecutiveMeddling. That's why people still have Christmas decorations, and Veronica describes Madison's birthday being "a rite of fall".
* {{Foreshadowing}}: This isn't the last of Leo, nor of Veronica's feelings for him.
* GoodCopBadCop: Played with; when they're about to interrogate [=LaRoche=], Lamb says he and Keith should play to their strengths, to which Keith asks, "So I'm [[StealthInsult good cop]]?"
* GPSEvidence: Subverted. When Keith and Lamb go to ask about a guitar string, the owner of the store identifies it as "a triple nickel antioxidant special order string we get for just one customer". It then turns out the guy is just messing with them though and it is an incredibly common guitar string that is exactly the same as any other.
* JerkassHasAPoint: Lamb was probably right about Gabe's feelings of "inadequacy", which explains why he's the SerialKiller.
* LiteraryAllusionTitle: The title of the episode, of course, is a play on ''Film/TheSilenceOfTheLambs''.
* PoliceAreUseless: Played straight with Lamb, of course, but subverted with Leo, even if he does get suspended for being tricked by Veronica.
* RescueRomance: Played with; Veronica falls in love with Leo because he rescued Keith, not her. Doesn't make Leo feel any better when he finds out she used him, though.
* SerialKiller: The E-String Killer is the A-plot here.
* ShoutOut: A number of them:
** When Keith says he's expecting Lamb and the mayor, a puzzled Veronica tells him she's going to have Creator/RodSerling wait on the couch.
** Mac says her parents are nacho and NASCAR people, and Veronica jokes that Mac is more "Falafels and [[Creator/FedericoFellini Fellini]]."
** When Mac sees Lauren for the first time, Lauren is reading ''Literature/TheWestingGame'', a mystery involving LoadsAndLoadsOfCharacters [[FridgeBrilliance that's ultimately solved by a teenage girl]].
** When Keith and Lamb first enter the guitar shop, Keith yells out, "[[Film/ThisIsSpinalTap Hello, Cleveland!]]". [[PopCulturalOsmosisFailure Lamb doesn't get the reference]]; Keith notes [[DeadpanSnarker it explains a lot]].
** When Leo tells Veronica he plays in a band, Veronica jokes, "[[Series/CopRock A cop that rocks?]] [[TakeThat What will they think of next?]]"
** The title of the episode is from the Hannibal Lecter book ''Literature/TheSilenceOfTheLambs''.
* SmallNameBigEgo: While Veronica isn't a small name, she happily agrees with someone when he tells her she rocks.
* StripperCopConfusion: Parodied; Leo jokes he was sent as a stripper for Inga when an armed robbery call came in, and that's how he became a cop.
* SwitchedAtBirth: The B-plot, involving Mac and Madison.
* WindowLove: Mac and Mrs. Sinclair, her biological mother.