High school can be brutal, as "Mean Girls" likes to show with its wild-animal parody scenes. "The DUFF" takes it to another level, revealing that Bianca, our protagonist, is literally referred to as the "Designated Ugly Fat Friend," or "DUFF," of her friend group. Furious, Bianca agrees to a deal with her childhood friend turned popular jock, Wesley: she'll tutor him so he can pass science and stay on the football team, and he'll teach her not to be a loser. The more time they spend together, the more their old friendship (and then some) rekindles, and they both start to realize just how much they've let the rules of high school popularity define how they view themselves.
