Myka and Pete are pinged to the suburbs, where a district attorney fell down dead - poisoned, it would seem, by the same chemicals used in lethal injections.
Pete also has some demons to work out - he had his yearly physical, and the doctor told him his testosterone was low, prompting him to leave no door un-knocked down. Yipes!
Claudia and Artie spend some quality time together trying to save the life of a street kid who's been writing hyper-advanced equations on walls and windows, going into a trance and then a seizure each time it happens. The boy, Nick, is able to describe what he sees in the trance, thereby leading Artie to the artifact thief.
The case in the 'burbs gets weirder and weirder, with two more residents getting stuck to one another, a third bursting into flame, and a fourth coughing up red clouds as if he's in a nerve gas attack.
Myka understands the connection - the town busybody, Janice, used an artifact created from the destruction of the salt mines of Sodom. She sprinkled the salt onto cookies and has been targeting the members of the board out of revenge (they refused to erect a bust of her late husband, and now they must die!). Anyone who ate those cookies suffers a punishment equal to what they believe is their greatest sin.
Pete being Pete, he ate one of the cookies of sin, and while Myka knife-fights a fully-crazed Janice, Pete's thrown through a second-story window onto a lawn, where he breaks his legs. Myka bags the artifact, but that doesn't reverse the horrible damage to Pete's legs.
Myka cradles her partner and asks him to confess whatever it is he needs to confess. When he finally tells the story of how, when he was still drinking, he got into a car accident that broke both his friend's legs. Pete himself walked away fine. When Pete is finally able to confide in his partner, his legs return to normal, and they return home.
Myka also has to have her yearly physical, and she learns a painful truth that she can't even share with her partner: she has ovarian cancer.