Miss Nelson can't control her crazy classroom because she's just too nice. But when she disappears, her replacement is the hard-as-nails, detention-loving, recess-canceling, homework-overloading substitute teacher Viola Swamp! With the Big Test approaching, the kids suddenly realize how much they miss Miss Nelson and they'll do anything -- including hiring a private eye -- to solve the mystery of her disappearance and bring her back.

Algebra should be illegal! At least that’s what Dahlia told her dad, who took her complaints straight to the school board. Now, parents are protesting polynomials, and algebra is outlawed at Dahlia’s school. Math books are considered dangerous, and teachers are closely watched to make sure they don’t talk about radicals. But Dahlia’s starting to think that maybe math isn’t all that bad . . . If Dahlia’s father is already on his way to the capitol to introduce a bill banning algebra from schools across the state, how fast will Dahlia have to travel to stop him?