Derek is upset that Sally continues to hang out with her ex-boyfriend Patrick. Derek believes that guys and girls cannot be friends, it always leads to something more. So in attempt to make her jealous he calls Kendra and asks to hang out with her on Saturday. Casey thinks Derek is being ridiculous to believe that guys and girls cannot be friends so she starts hanging out with Noel, who in turn thinks that she likes him back.
Meanwhile George has a new friend at work named Terry who just so happens to be a girl. Edwin is worried that Terry has other motives for being George's friend and wants to break up his marriage.
Songs: Say When -- Whoa
There's a new guy at school who decides to rate all the girls. Casey finds out that he only rated her a 6 1/2 out of 10 and is upset. Kendra decides to use the ratings the new guy gave the girls to select models for a fashion show.
Truman keeps asking Casey out and every time she says no, as a result she has been having dreams about him. Meanwhile Edwin starts snooping on the McDonad's and Casey's dream diary goes missing.
It's "Take Your Child to Work Day" but the Venturi-McDonald house is doing it a bit differently. Instead it's called "Take Your Stepkid to Work Day" and Casey will go to work with George while Derek goes to work with Nora. Meanwhile Edwin fakes sick to stay home with Lizzie and Marti who are actually sick.
Casey is stuck with Truman as her fencing partner in PE. Meanwhile, George buys a ping pong table and it puts Edwin and Derek to be in competition with each other.
It's George and Nora's two year wedding anniversary and George has thrown the family a Mexican fiesta. Nora decides that its time the family learns about Operation Disengagement, Derek and Casey's plan to break up George and Nora.
Casey agrees to go out with Truman but things don't go exactly as planned. Meanwhile, Edwin's friend Teddy returns and won't leave the Venturi-McDonald family alone. While everyone else wants him to leave, Derek decides to take him under his wing and George is away on a business trip.
As Prom approaches the Venturi household is full of surprises Derek announces a new love, Casey gets back with an old love, and Nora and George announces the biggest surprise of them all to the family.
As graduation day approaches, a worried Casey is having difficulty writing her valedictorian speech, which she blames on her fear of Derek pulling a prank and ruining it until Derek points out that she's actually afraid of what the future holds. Meanwhile, Edwin is concerned that he won't be able to live up to Derek's reputation at J.S. Thompson High when he goes there in the fall. The family celebrates Casey and Derek's high school graduation and the two make a very awkward announcement: that they are going to the same university.