The rich kids’ version of a Sadie Hawkins dance is called a Flipside Formal.

Emma tries to enlist Laurel while Thayer ignores Ethan. Thayer’d like Emma to rope Ethan in, but he won’t cave.

Rebeccannie tells Sutton she doesn’t think she can trust her.

Looks like the big secret Alec told Theresa was about the twins. She can’t tell Dan because so far, everyone who’s learned about the secret has wound up dead. She doesn’t tell him that, just that it’ll put him in danger. Doesn’t lawyer-client privilege hold after they’re no longer your client? Or is it because he was exonerated so can’t be tried for it again so it doesn’t matter? Either way, she’s keeping her mouth shut.

Kristen’s hired an accountant to go through her and Ted’s finances in case she decides to go ahead with the divorce. Laurel comes in and Kristen confides that Ted’s been making regular, small cash withdrawals which total up to $20,000. Laurel goes to Ethan for advice.

It sounds like Theresa may finally be ready to confide in Dan, but just then, Derek Roger’s mother comes up with a bag of his she found buried under a rose-bush. It contains $20,000.

Laurel tells Emma about the 20K. Thanks to Ethan, she’s finally in. And so is Ethan, it turns out. They tell him he’ll be taking Emma to the formal. As he’s getting dressed at the trailer, he overhears Dan and Theresa discussing the 20K Derek stowed.

Emma texts Mads, who’s moping over Jordan. She claims that Ethan’s taking Sutton to the formal and she and Thayer are hiding out. Alec persuades her to go to the dance anyway.

Ethan picks Sutton up, and puts her into the limo. He closes the door and it immediately speeds off with Thayer behind the wheel. At the dance, Ethan tells Emma what he overheard about the money (except the amount). The talk. The chemistry is palpable, but she says she’s really with Thayer. He says he really knows.

Thayer finally pulls the limo over so Sutton can get out and get some fresh air. She tends to get carsick when she rides in the back seat. Me, too. She’s pretty much figured out the plan, and knees him in the groin and steals the limo.

Alec goes to see Kristen. He brought wine.

At the dance, Jordan attempts to explain himself to Mads (he had to ask Laurel under Rebeccannie’s orders). Laurel does a better job when she lets Mads in on the current switch, thereby revealing she knows about the twins. Sutton texts Rebeccannie to warn her of the switch and asks her to meet up. When Rebeccannie leaves, Emma spies her chance and heads after her. They’re hoping Rebeccannie will think she’s Sutton and spill something. Luckily, she’s forestalled by Mads, who’s upset at being left out of the loop. After Mads runs off in a huff, Ethan comes up and urges Emma to go after Rebeccannie. She paid Derek 20K and then killed him. For Emma, the penny drops.

When Sutton meets with Rebeccannie, she suggests bringing Emma in to the plan. Her mother points out that even Ethan has turned against her now, and leaves to hook up with Ted. Sutton goes to bitch at Thayer and Ethan, who are looking for her. When she starts in on her line about Emma “stealing” her life, Ethan finally lets her have it. Sutton says they’re done, in fact, she’s done with all of them, and storms off. Thayer goes to find Emma, refusing Ethan’s company.

Mercer house. Alec and Kristen reminisce. Alec comes within millimeters of kissing her, then abruptly leaves.

Country club. Rebeccannie and Ted stroll on the grounds. She reveals that she wanted to ask him to dance at the Sadie Hawkins dance where he, Alec, and Kristen were seniors (Kristen asked him and made him very happy), and she was a sophomore, but didn’t have the guts. She asks now. He says it’s the Flipside; he can’t say no. They slow-dance.

In Thayer’s room at the club, Emma tells him her suspicions: Ted is her and Sutton’s biological father. Derek was blackmailing him, and maybe Ted killed him, not Rebeccannie.

Mads is on a lounge chair by the pool, getting drunk. Ethan joins her since they’ve both been left out. Mads tells him she knows he’s not over Emma and says he should go for it. They decide to finish the bottle and talk all night.

Emma decides to give up her V card to Thayer.