At a neighborhood game night, Peter wins at Trivial Pursuit. He doesn't realize that Lois is reading him questions from the preschool edition, though and declares himself a genius. Brian, fed up with Peter's lording his Trivial Pursuit victory over everyone, tells Peter about a test for geniuses. Peter takes the test and finds that, not only is he not a genius, he's  mentally retarded.

Peter is upset about this outcome, until he realizes that he can get away with anything, because he's retarded. So he takes advantage of being retarded to do all kinds of socially inappropriate things. Peter even gets assigned an "inspirational social worker" who teaches him to give "high fives". At a fast food restaurant, Peter tries to steal the deep fryer and ends up dousing Lois with boiling oil. Then CPS shows up at the hospital to take the kids away because Peter is mentally unfit to be a parent.

Cleveland takes the kids in, and lets Meg have a sleepover with her friends. Quagmire hides behind the couch, hoping to spot some hot teenage action, but leaves in a huff because Meg and her friends are so boring.

Peter initiates a plan to get the kids back - by proving that Cleveland is a worse parent than he is. He tries to frame Cleveland by putting a bunch of hookers in his house. At the court date, Peter calls a surprise witness - "the ghost that never lies", who only he can see. That doesn't work so well, but Peter pulls out an impassioned speech about how much he loves his kids. Unmoved, the judge refuses to give the kids back.

Fortunately for Peter, Lois makes an amazing recovery and gets released from the hospital, and gets the kids back. This was a pretty good episode overall, but I felt like the ending wrapped it up a little too abruptly. Sure, this is animation, and it doesn't have to be realistic, exactly, but like all fantasy, it does need to make sense within the boundaries the fantasy sets. One minute, Lois is wrapped head-to-foot in bandages, recovering from being doused in hot oil; the next she's strolling in the door, fully recovered, with the kids - who were just taken away? Wow.

I don't know, it just seemed to wrap up a little too quickly for me, like they ran out of time and were like, "Oops, let's wrap this up now". Other than that quibble, though, it was a fairly funny episode.