Meg convinces Brian to take the SAT's for her, but when he tests poorly, they start to suspect that Brian might not that smart after all. Peter decides to spend the day showing Brian the joys of being stupid and the benefits of having a low IQ.

Lois takes Peter to open a checking account, and they discover that his first name is actually Justin, which Peter adopts as the name of his younger "bro"-style alter-ego. Then, Peter/Justin throws a party, during which Quagmire unknowingly gets into some trouble with his mother .