Cut back to the scene from the teaser. It's clear now that Jen is talking to Amy as she packs. After she hangs up, Derek busts into Jen's room, demanding to know who she was talking to. She won't tell him. Why does he even care? He demands to know who Jen said "I love you" to and where she's going. She won't tell him and demands he leave the room. Where are their parents? Hello? He thinks Jen and Adam are an item because he picked her as insurance for the race. Jen says this is not the case, but won't answer his questions as she picks up a bouquet of roses and leaves. I'm just going to assume that she picked up the roses on the way home, right?
She stomps out of the house with her roses and her suitcase and finds Adam waiting with his car out front. He says he just wants to talk. Has she, perhaps, ever considered the possibility of a three-way? Okay, he doesn't say that. He does insist that he just wants to talk and he can't find Amy. I guess he doesn't notice the SUITCASE and ROSES that Jen is toting and draw any conclusions from that. She agrees to get in the car so he can talk to her. As they drive off, we can see that Derek has been watching this all through a window. He comes to the conclusion that Jen is dating Adam and is very jealous. Er. I mean, "angry."
Derek comes storming out of the house to follow them just as Tru's car (well, Harrison's, actually) comes to a sputtering halt in front of the house. Tru whines that Harrison never changes his oil. Yeah, the car has clearly been meticulously cleaned on a regular basis, but Harrison never looks after the internal workings. Stupid show plot devices. She sees Derek and hops out of the car and rushes over to him. He says he's a bit busy, but when she explains that she wants to stop Jen and Adam, he realizes they're on the same page (but, as it turns out, not reading the same book), and allows her to ride along with him.
Adam drives really fast as he grills Jen about how long it's been going on. Jen says it's been a few months. Adam is shocked. She says she was trying to convince Amy to tell him the truth. He speeds up.
In the chase car, Derek is bitching because Adam is sleeping with his sister. I bet he thinks he can teach Adam a little discipline. Tru tells Derek that they're not sleeping together. Derek doesn't believe her.
In the other car, Jen tells Adam to slow down; what happened wasn't his fault. She tells Adam that Amy didn't know how to tell him what was going on. She says that Amy really does love him. But Adam points out that Amy's in love with Jen. Jen doesn't respond at this, but Adam brings the car to a screeching halt right by the guardrail for Lakewood Cliffs. He notices the necklace on Jen and says he was going to buy it for Amy, because he saw her staring at it in a store window. Now, of course, he understands why. Well, at least he didn't give it to Amy, only to have her "re-gift" it to Jen. Amy still wants to be friends with Adam, Jen insists.