High school sleuths P.C. Hawke and Mackenzie Riggs quickly regret their decision to take a killer calculus class at Columbia University. Not only is the math work more than anything they’ve ever tried before, but their professor loves to ridicule anyone having trouble keeping up—which is everyone in the class.

But as mean as she is, it’s hard to imagine who might hate Professor Dunaway enough to murder her! When she’s found pinned to the blackboard with a crossbow bolt shot through the window, there’s no shortage of suspects—both students and parents. But a lot of things about this grisly case just don’t add up for P.C. and Mac.

Brimming with action, Pulitzer Prize–winning author Paul Zindel’s popular P.C. Hawke mysteries include The Surfing Corpse and Death on the Amazon.