Luke and Summer were engaged in the second grade.
Marissa mentions how she and Summer first fought in 5th grade when Marissa sat with Luke at the back of the bus on a trip to a museum. This was mentioned in Season 1 Episode 2.
Marissa: I can't deal with this right now.
Summer: Well you're gonna have to, cause now Coop, we're sisters.
Marissa: Right, which means you're not my mom.
Marissa: Wow! Well, aren't you a regular Veronica Mars? Way to solve this week's mystery!
Seth: What? The guy who produced the ball of energy from his chest and then destroyed the world? I think it's pretty self-explanatory.
Summer: Looking good, Coop! Look very Kate Moss pre-Vanity Fair cover.
(When Marissa is spotted with Volchok by Seth and Summer)
Summer: Oh my God.
Seth: So if the body doesn't lie...
Summer: Then it's saying ew!
Seth: Ew? Or touch my pooper?
Marissa: Fine, well why don't you take your emo boyfriend, drive off in your beemer and go home to daddy's mansion?
Summer: Oh yeah, why don't you go with Volchok to one of his heavy metal vomit parties and like listen to heavy metal and like, vomit?
Marissa (laughing): Wow. You're being so lame.
Summer: Not as lame as you.
Summer (enthusiastic): Engaged?
Marissa (tired): You guys are engaged?
Summer: I mean, you may be Mrs. Cooper-Nichol Cooper-Roberts, but if you make my dad happy..
Neil: She does.
Julie: I do.
Julie: Vamanos por favor!
Maid: I'm from the Philippines.
Marissa: I think I have a bit of a head cold.
Summer: As long as you don't have any other infectious diseases.
Summer: What are you getting drunk?
Marissa: More like staying drunk.
Faster Kill Pussycat by Paul Oakenfold (feat. Brittany Murphy)
Spin Me Around by The Surge
A Night In Vegas by Victor Malloy
When You're Gone by Luther Russell
Young Shields by Casiotone For The Painfully Alone
Meredith by Oceansize
Summer tells Marissa that she can go with Volchok to one of his Heavy Metal vomit parties. That same expression was used in The Breakfast Club when Claire was talking to Judd Nelson's character John Bender describing his lifestyle.
Marissa: Wow, well aren't you just a regular Veronica Mars, way to solve this weeks mystery!"
Veronica Mars is a girl detective, on the CW show Veronica Mars.
Seth tells Ryan he likes him the way he is, and refers to Ryan as Boo Radley. Boo Radley is a mysterious character in the classic novel To Kill A Mockingbird.
Title: The Secrets and Lies
This is a reference to both the 1996 movie Secrets and Lies and the 2003 tv series of the same name.