While Giardello is busy sending off an old friend to retirement Pembleton and Bayliss investigate the murder of a dog, Howard and Felton argue over whether Felton finds Howard attractive while dealing with a drug-related homicide and Bolander and Munch take Dr. Blythe's son on a ride along. Meanwhile, Crosetti takes care of the bed-ridden and blind Thormann.

A gas leak causes the detectives to evacuate the building, so they relocate to an old bank building. Lewis is paired up with Kellerman on the murder of a woman. Sergeant Howard tries to carve out a place for herself with the other detectives, but her efforts prove unpopular. Pembleton has trouble adjusting to the new surroundings and his wife's pregnancy. A cameraman who was at the scene of the murder has who he thinks is the perpetrator on tape; however, when he brings the tape to Gee, he is thrown out before he can say why he's there. The cameraman eventually strikes a deal with Lewis and Kellerman.

A trash-talking radio talk-show host makes a proposal to his listening audience. Lewis announces to Kellerman that he is getting married today, then he throws up. He motivates the rest of the squad to help him with the final details as he is getting married ""tonight after the shift ends."" Kay brings her sister with her to the station. Since the whole squad is busy with Lewis' wedding, Gee takes Howard out to work the homicide of the radio talk-show host. One of his listeners took him up on his proposal. Munch is skeptical about the Lewis wedding; he thinks it's an elaborate practical joke. Bayliss and Kellerman vie for the attention of Kay's sister. Gee shoots and kills a potential suspect, but the suspect was in jail at the time of the talk show host's murder. The guy who fingered him admits that he did it as a joke. The wedding is no hoax. During the festivities Pembleton's wife goes into labor.

Lewis and Bayliss investigate a homicide at a boarding school. Gee goes to Frank's house to pick him up for a trip to the gun range. Kellerman wants the investigation into corruption in his old arson unit to move along, but he finds out that all the real guilty parties have made plea bargains. Frank's firearm test looked promising. The tiny little voice in Bayliss' head tells him that McPhee Broadman might be their suspect despite the fact that his mother is a powerful judge in Baltimore. A student comes forward and confesses to the student's killing; however, the detectives aren't convinced he alone was responsible. Frank passes the exam and can return to active duty, but as far as he is concerned the real test is in the box.

Their rotation in robbery is up, Frank and Tim return to the homicide unit. They find that citations are being handed out to the unit and a delighted Gee, whose clearance rate is the highest it has been in five years. Kellerman and Lewis are also scheduled to return. Howard is still on assignment with the fugitive squad. Additions to the unit through rotated assignment include Det. Ballard who actually comes from a Seattle homicide unit, Det. Falsone and Det. Gharty. Falsone and Gharty worked with the unit on the Felton case last spring; however, nothing is mentioned about the status of that case. (Sharp-eyed viewers note that Felton's name is still in red under Pembleton's name on the board.) Meanwhile, Gee attends a black tie function honoring Felix Wilson, a respected member of the community. Because he grew up with them, Gee sits at a table with Felix, his wife and their family. Everyone attending the function at the hotel is kept late because the body of a woman is found dead in t

Homicide is called in when a woman is distressed at the fact the Dr. Turner helped her brother stop suffering from his colon cancer by injecting him with a lethal dose of morphine. Other members of her family were comfortable with the way he died. Pembleton and Bayliss investigate the issue of murder or mercy. Ballard and Gharty spot their city goats at a shopping mall, where Gharty was using Ballard as a consultant in his purchase of a gift. Stivers and Falsone catch a case where a schoolgirl and the owner of a pizza parlor are murdered during the holdup of the pizza parlor. Kellerman confronts Judge Gibbons and tapes their conversation about his ruling in making the wrongful death suit a jury case. Ballard and Gharty round up their city goats after they confront their mother. Gee warns the rookie homicide detectives, Stivers and Falsone about the baggage that comes with working their first case involving the death of a child. Pembleton and Bayliss' investigation of Dr. Turner's pract

Sheppard and Bayliss await the trial of Luke Ryland, the Internet killer. A number of delays keep the hearing from being held; the last time it is because Danvers can't make it due to being held up in another trial. Because of a technicality in the law, Ryland is set free. Bayliss is outraged and winds up pushing Danvers, who later threatens to put Bayliss up on charges. Gee's daughter Teresa arrives, to help with the celebration of her father's promotion. Gee asks Bayliss to apologize to Danvers and Bayliss declines. Lewis and Falsone look into the murder of a drug addict whose husband looks like the most probable suspect. The victim's mother-in-law isn't very cooperative and her sister is a nun who thinks her brother-in-law is an architect. Gee worries about whether or not he will be able to perform in his new role as Captain of the property crimes division, later he turns down the promotion. Bayliss and Lewis have words about the way each other handle their memories of the past.