Bayliss continues his relationship with the artist, but she's told her boyfriend. When she tells Bayliss that her boyfriend hit her upon hearing the news, it makes Bayliss so mad he confronts him. Pembleton and Bayliss investigate the death of a woman who's received a delivery of fresh flowers, although she's been dead over two weeks. Bolander and Munch investigate the shooting of Thorne's source, who's linked to a cocaine cartel, then Thorne is shot. Gee tries to get the department to get him a replacement for Crosetti. Thorne's daughter decides to keep his newspaper going. Beau tries to find out where his wife has moved the family. With Meldrick and Bayliss' disagreement over the artist, Munch is left without partners for the bar. Bayliss goes over the edge when the artist dumps him, so he holds up a liquor store for 11 cents; Pembleton gets him out of it.

Sheppard and Lewis investigate the death of a man who has a twin brother. Gharty talks about wanting to live his life; he and Ballard go to the hospital to investigate the death of a teenager. Bayliss has interest in Sheppard; later he seeks advice from Stivers, who tells him to get in line behind Lewis and Falsone. Lewis and Sheppard interview the remaining twin and his mother; she confirms his story and they try to point to the dead twin's girlfriend. Meanwhile the friend of the teenage victim in Ballard and Gharty's case confesses that his friend wasn't shot in Baltimore, but rather D.C.; he drove his friend back to Baltimore so their parent's wouldn't ""kill them"" for buying drugs in D.C. Gee hopes to get the case moved to D.C. Mike Giardello puts in for his FBI transfer, but the only openings they have in the area are for liaisons to local police departments. He interviews with Gaffney, who is so open to the idea, he can't wait to tell Gee. That's something Mike was going to wait f

Munch spreads his usual Christmas cheer. Russert, who misses detective work, joins Meldrick on an investigation into the murder of a material witness, when she discovers she knows something about the victim's case. Munch and Bolander investigate the death of a man in a Santa Claus suit and Munch spends the evening with whom they believe is the victim's son. Beau buys Christmas presents for the kids, although he still doesn't know where Beth and the kids are. Bayliss searches the station in search of a game of hearts.

A convict is released from prison and begins to get his revenge on Frank by frustrating the investigation he is currently working on and also by terrorizing his wife.

The squad returns to the station. The FBI joins with the detectives to stop a ""thrill killer"" who's working his way north on I-95. Gee tries to reconcile with his daughter. The killer smells a rat at a roadblock so he bails out of his pickup. Everyone mobilizes to find him and when they do, the suspect in custody, while identical to the killer, claims he is innocent.

Gee is sent upstairs to see Barnfather and everyone speculates about the vacant Captain's position. Lewis and Kellerman are sent to Pennsylvania to extradite a woman back to Baltimore where she is a suspect in the murder of her husband. Munch tries to find a videotape in Brodie's pile. Later after reviewing the tape, they discover a key piece of evidence isn't contained on the tape. Munch wants the tape erased, but Brodie delivers the tape to court and that results in the outcome Munch feared. On the trip back from Harrisburg, Kellerman convinces Lewis that they have time to stop at Neptune's Castle and they lose the suspect, for a moment. Later they lose her again but find her at the house of her dead husband's mistress, delivering a hat. Much to everyone's surprise but not the viewers Gaffney is promoted to Captain over Gee. Captain Gaffney lays down the law.

Lewis and Kellerman investigate a series of homicides that put them into the middle of a drug war. Kellerman suspects that Lewis is seeing someone, but he doesn't ""kiss and tell."" As the red piles up on the board Gee gets edgy. Kellerman seeks comfort from the godmother of the daughter of the victim's family. Kellerman and ""Drak"" have a confrontation. At a ""Peace on our Street"" demonstration, the current drug war is ended.

The Internet is stage for a ritual murder, which was staged -- which was staged, or was it? The body is found the following morning and Sheppard takes the call, her first since the beating. Since Lewis can't be found, she partners with Bayliss. Second shift detectives Bonaventura and Austin catch word of the day shift's case. It seems the victim in Sheppard's case was a witness they had interviewed the day before about an online murder hoax. The detectives are informed about another murder that is scheduled for midnight. It's a red ball. The detectives try to put the clues together, but come up with nothing and must wait until the netcast begins before they can trace the killer. The trace is successful, but when they arrive at the scene, the killer has left them a computer with the words ""Ha Ha Fooled You."" Barnfather wants Bayliss reassigned as primary if something doesn't turn up soon. Sheppard goes online to flush out the killer. He advertises another murder will take place at www.i

A new Baltimore Sun reporter gets into the middle of Frank's investigation of the death of a county cop who was shot because of drugs. Gee likes her style. Mike's brothers, Drew and Greg, come to town, who want to take him and his boat to Miami to set up a charter service. Mike learns that they are on the run from a bookie that Drew owes $18,000. To pay that debt, they've stolen Babe Ruth's Baltimore uniform from another bookie with the intent of selling it. Lewis and Cox go in search of the Kellerman boys. They find them in jail where they spent the night after trying to return the uniform.

MGee (Mike Giardello) and Ballard investigate a double shooting at the home of a prominent sports doctor and his wife, a dermatologist. The doctor (who was wounded) did not realize the deceased (thought to be a prowler) was his sister-in-law. Munch contends with the IRS; his Waterfront partners want him to make sure that his cousin, their accountant, has been paying their taxes. The Waterfront needs a loan to pay for some improvements. Gharty has taken the day off, to take care of personal matters, like his recent separation from Flora. Munch has his hearing with the IRS; he owes $30,000 in back taxes. Bayliss and Sheppard discuss his sexuality and the possibility of a date. Falsone takes MGee and Ballard to meet an old fight man who knew their doctor. Ballard becomes excited while watching Falsone spar in the ring. MGee and Ballard's investigation lead them right back to the doctor's house, where his wife may be guilty of conspiracy to commit homicide. Gharty stops by the Waterfront t

Brodie suggests that a classmate of his named Schack should be a suspect in the death of the student that Munch believes committed suicide. Frank and Mary meet with their marriage counselor and they begin to air some issues. Bayliss and Kellerman try to link together two deadly bombings. Schack attacks Brodie, but he can't prove it. He does offer a way to get Schack to admit to the murder. Frank tells Mary that he will agree to getting Olivia baptized. Mike connects the two bombings; the victims were both connected through the death of the Korean grocer who was murdered by a man who worked for Luther Mahoney. They suspect that there may be more bombs, including one at the courthouse where Meldrick and Julianna are waiting to meet with Judge Aandahl and Danvers, both of who were associated with the Korean grocer case. Frank arrives late to the baptism; Mary takes this as a sign and tells him she is leaving him for a while.

When the men are nowhere to be found, Sheppard and Ballard team up to investigate the death of young girl, who's a teenage gang member. With the wedding one week away, Billie Lou asks for Munch's help with her neighbor's abusive boyfriend. After Munch approaches him strongly, the boyfriend retaliates by coming to the Waterfront and slamming Billie Lou's head on the bar. Munch claims he came on strong with the guy, because his ""testosterone riddled behavior"" was due to the celibacy Billie Lou imposed on him, to make their wedding night more special. Billie Lou wants to delay the wedding until the welt on her forehead goes away in about 3 weeks. After Sheppard and Ballard solve their case, Sheppard reminds Lewis that his problem with her is not going to keep her from doing her job.

Ballard and Bayliss are called to the scene of the mysterious death of a woman, whose body is found at the bottom of a forty-foot cliff. This victim was to be married the following morning. The two detectives work to determine whether the death was accidental or intentional (via murder or suicide). Meanwhile Sheppard and MGee begin investigating the death of a movie patron, whose body was discovered after the show ended and the theater cleared out. MGee mentions to Sheppard that his sister is about to have a baby, which means Gee is about to become a grandfather. Their investigation reveals that the movie patron was regularly loud and obnoxious and thus bad for business. When an overdose of a sedative is found in his bloodstream, the detectives question the theater owner, who was currently in litigation with the victim. Unfortunately for Ballard and Bayliss, their case remains unsolved.

Danvers brings news of his appointment to the District Court bench as the investigation of a government official named Janine McBride continues in New York. Their prime suspect Chesley Purcell is dead and her shooter is in the hands of the Feds. The Baltimore detectives investigate the background of Chesley Purcell and it turns up the name of a man in prison who still appears to be running his organization. This crossover starts on Law and Order S09E14 Sideshow (I).

Night has fallen and the crisis is no closer to being resolved. Gee demands that Barnfather make a decision. Frank continues to trying to adjust. Frank insists on going to the hostage scene. The identity of the hostage-taker is made when he demands that his pig be brought to the school. When the pig doesn't arrive in time, he sets a fire and seriously wounds a hostage (who later dies) and then becomes badly burned. Brodie takes issue with Munch's treatment of Pembleton. The paperwork gets completed and the hostage-taker is formally charged. Frank makes a decision regarding his recovery.

Kellerman assures Lewis that he is seeking some professional advice; he also takes some time off. Lewis is assigned to work with Pembleton and neither is happy with the situation. Together they investigate the murder of a wealthy woman. They suspect the brother may have had a touch of sibling rivalry. Meanwhile, the brother insists that the police have stolen his sister's diamond ring. Mary tells Frank that she thinks they need to talk to a marriage counselor. Cox investigates whether the missing diamond ring might have been taken by one of her staff. She gets Brodie to help her add some video surveillance to the morgue. Mary asks Tim to be Frank's partner again.

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.

Bayliss returns to duty to discover the bosses have renovated the squad room in an attempt to make everyone forget the tragedy of last May. Gharty and Ballard have also returned and Ballard debates about whether she should ask Falsone to the Lodge party. New detective, Rene Sheppard, tells her just to go for it. Seizing the opportunity, Lewis goes for it and asks Sheppard to the party; it seems that he and Barbara have separated and are on their way to divorce. Meanwhile, Falsone speculates if he should ask Sheppard to the party. The first case Bayliss catches, now partnered with Munch, involves the dismembered body of Angelo Faltislo, a friend of Gee's cousin, Mario Giardello. Stivers and Falsone's case is similar: Leo Grimaldi, another friend of Mario, is also found dead. When Gee goes to question cousin Mario, he finds Mario's body in the same condition as that of his friends. Gee's estranged son, Mike Giardello, an FBI agent in Arizona, returns for the funeral. Mike asks Falsone (w

A woman brings to the homicide unit her mystery-writer husband's videotaped declaration that his literary agent is responsible for his murder. Ballard and Gharty catch the case -- only there is no body or crime scene. Meanwhile, Munch and Bayliss investigate the death of an elderly woman that occurred during a break-in -- was it a homicide? Munch would rather leave for his weekend rendezvous with Billie Lou. Ballard and Gharty's investigation becomes a red-ball as they find evidence in the writer's office that a crime was committed. A break leads to the arrest of the literary agent and his accomplice, although Danvers can't guarantee a conviction. Falsone asks Ballard if she would like to go out Saturday night; just then the jury comes back. And a sharp-eyed juror insures that justice is done.

Ballard is annoyed when she finds out that the fact that she had a date with Falsone is around the squad room. Munch has a doctor's appointment and he's not talking about it. Dr. Griscom calls on the homicide unit when he sees a number of deaths that are related by a poison named phosphozine. The FBI steps in on the poisonings and they put MGee in charge of a task force; they consider it an act of domestic terrorism. One of the victims was a priest; two others were his parishioners. Gharty suspects the communion wine. Following this idea, wine bottles are collected from churches around the city. A needle hole is found through one of the corks. A citywide canvassing of all places where wine can be purchased is launched. Gee disagrees with the bureau's policy of keep information from the public. One possible suspect is captured; however, strange as he is, he's not the one. Through an internal leak, the media is alerted and warns the public, sparking chaos. MGee suspects the source of the

The new Chief Medical Examiner (CME), Julianna Cox, speeds into town. An FBI agent, Pandolfi, conducts interviews with the squad about Kellerman. Frank looks for way to celebrate his anniversary with his wife. The new CME arrives on the scene of a homicide that Lewis and Bayliss are working on, they lay down their respective ground rules. Bayliss' murderer confesses to committing another crime. Kellerman is worried by the ongoing investigation and takes it out on another arson officer. Brodie offers to make chili for the Lewis family but the dinner turns into a fight for Meldrick and his wife. From a suggestion by Frank, Bayliss and Lewis get the other body exhumed and checked out. Frank and Mary celebrate their anniversary. Bayliss gains some insight into the new CME.

An article appears in The Baltimore Sun about Kellerman and the other members of the arson unit who are under investigation. Munch investigates the death of women whose husband returned home to find her dead, cause unknown. He suspects the husband but Cox thinks differently. Pembleton tries to help Bayliss close the Lambert case. The article puts Kellerman on edge and he goes to Roland's office where he discovers Roland is a federal witness. This incident gets him suspended until he takes a polygraph test. Brodie gets an offer to stay at Kay's place. Munch presses his witness and breaks him but Cox's evidence still says otherwise. Kellerman takes the test and while waiting for the result tells Lewis the truth. Cox visits Munch's suspect in his cell. Frank reflects on his past and the future. Kellerman passes the polygraph, but so did the federal witness; one of them beat the test.

Lewis is transported to the hospital, as is the passenger of the car that MGee hit. Gharty is worked up about women and finances, because he and Flora and their lawyers are going to be working out the financial details of their divorce. Gee & MGee are not interested in cooperating with the bounty hunters; however, Knoll is the only one who can get any information on the whereabouts of Errico from Errico's mother. She has promised to page Knoll when her son calls. (Joe Errico has gone south to Miami.) Knoll offers to pay the expenses of having homicide detectives go to Miami and work with him, but Gee declines that generous offer and sends his detectives separately. In Miami, Bayliss and MGee work with Knoll to capture Errico. Knoll offers to split the huge bounty with the homicide detectives, which they of course refuse. MGee decides that the best use for the bounty might be for the man whose wife had died from the injuries she sustained in the car accident.

Lewis and Munch begin to investigate the death of a Buddhist monk beaten to death. Lewis isn't interested in working the case with Bayliss, whom he feels, may become too emotionally involved. Ballard and Falsone agree to call their relationship quits. Ballard and Gharty's case involves a man who was shot down in the street; the three witnesses that saw the shooter all have different recollections of his appearance. As a result, their prime suspect cannot be charged. Gee asks for Bayliss's assistance in the Buddhist murder and to Lewis's dismay, Munch abdicates his position in the investigation to Bayliss. Lewis and Bayliss take different approaches to the investigation. Bayliss's approach leads him to the man who committed the crime, but cornering his suspect leads to a showdown with guns and Bayliss fires a fatal shot. Later Bayliss tries to reconcile the shooting with his own feelings about being a Buddhist and being a cop.

Crosetti and Lewis investigate the shooting of a fellow police officer whom Crosetti regards as a son, Howard suspects a rabid Spiro Agnew fan of murder but ends up solving the Calpurnia Church case meanwhile Bolander makes a friend whose death interrupts his date with Dr. Blythe.