The stories in Weinberg's Residue Class Mystery series keep getting better and better, as the team of young genius mathematicians grows more experienced at dealing with villains. Still, they're more than capable of making mistakes, usually caused by outsmarting themselves.
In this episode, they pursue a professional killer who has challenged their abilities by committing "random" murders. Once again, theire ability with numbers and formulas leads the way to the killer. It's a mystery, so you can be pretty sure they'll solve it in the end, but it's the fits and starts of the trip that make the journey interesting. It's not your run-of-the mill mystery.l