Lewis and Crosetti uncover a woman who's been killing her husbands for insurance money. Howard tries to keep her cases-solved record perfect, but she is reassigned with Felton as her partner. Bolander convinces Munch to help him finish up an unsolved case. A new guy, Tim Bayliss, from the mayor's office gets his first case in homicide, the murder of an 11-year-old girl. His partner Pembleton, we find out, is less than enthusiastic to work with him or anyone else in the unit.

Bayliss and Pembleton continue to struggle with the Watson case. Bolander and Munch discuss ""iguana style"" and are called to check out the homicide of a victim that isn't dead, at least the first time they're called. While checking out some leads for the Watson case, Crosetti gives his theory on the conspiracy to kill Abraham Lincoln. Lewis wants to flood Memorial Stadium. Bolander expresses an interest in Dr. Blythe; Munch advises and sends flower's in Stan's name. Danvers needs a stronger case; however, Howard is frustrated with a dead end. Then the ghost of the victim leads her to the undiscovered proof. Tim attends Adena's funeral.

Crosetti lays out more theories on his Lincoln assassination conspiracy theory. Then Gee comes in with news that Crosetti's friend Chris Thormann has been shot. After they follow up on a new lead in the case that takes them nowhere, frustration begins to set in for Bayliss. Bolander meets his neighbor, a man who works with wood. One of his projects is a coffin. Together, they drink Stan's beer and discuss life, love, and etc.. Kay and Beau's suspect in a murder hired a hit man to kill a man she disagreed with about a bust of Spiro Agnew. Their case leads to a solution for Meldrick's case involving the ""black widow."" Crosetti demands that he get the case to solve Chris' shooting. Stan meets Carol for their first date; however, they get interrupted when his neighbor is found dead. Gee talks with Bayliss about his frustration. Chris is going to survive, but what level he will recover to is yet to be determined.

Bolander and Munch tackle a case, but Stan keeps throwing his old partner's name at John. Evidently the date with Carol didn't go that well, he doesn't want to talk to her or about her. Pembleton (with Felton) and Bayliss follow different hunches in the Watson case. Chris' recovery is amazing, but it will take a lot of therapy and his getting used to being blind. The suspect in Chris' shooting gives himself up, to prevent being the victim of police justice. Lewis isn't as sure as Crosetti that their suspect is the one. Barnfather lets out a key piece of evidence to the media, taking the wind out of Tim's line of questioning for his suspect. Tim lets him know how he feels, and even though he is right, he must apologize. Pembleton and Felton discuss various racial issues while following up their lead. Carol finally catches up with Stan. Munch wants nothing to do with Karaoke at the bar, but finally gives in and enjoys himself. Frank gets hold of evidence that will allow them to follow up

Pembleton and Bayliss have only twelve hours to grill their prime suspect in the Adena Watson case before they must let him go.

Gee must help an old friend get used to his retirement. In their first case following the unsolved Adena Watson case, Bayliss and Pembleton check out the death of a police dog. Howard and Felton track down a drug dealer that is wanted for a torture / murder. Crosetti continues to help Chris deal with his recovery and finds out his wife is pregnant. Bolander meets Carol's son who later accompanies him to a crime scene.

A Chinese political refugee is murdered. Bolander and Munch investigate a murder of a man whose body is found in the park. Lewis and Crosetti go to the Chinese Embassy in Washington while looking into the murder of the Chinese political refugee. After they leave, a U.S. government official tells them to back off. Gee is looking for Pembleton because Pembleton may be up for a promotion. Howard nearly botches her testimony against the drug dealer. Pembleton is up for a promotion that he may not want.

The building is checked for air quality and later Gee is outraged when the asbestos removal teams come in without his knowledge. While investigating the death of a gang member, Bolander and Munch use an ""Electrolyte-Neutron Magnetic Test"" to break a boy into giving up the guilty party. Felton and Pembleton can't understand why their partners are trying to quit smoking, again.

On a slow and hot September night in the squad room with no air conditioning, the detectives spend the night together. Bayliss has a new suspect brought in on the Adena Watson case, a twelve-year-old boy. Munch deals with his breakup of his latest relationship. There is a mystery about a solitary lit candle in the squad room: who lights it and why? Bolander debates about calling the Dr. Blythe for a date. Santa Claus drops by depressed about today's society. Gee finds an abandoned baby in basement of the building.