A homicide on the Brooklyn Bridge and the murder of a 24-year-old heiress are investigated. In the first case, a pair of bungee jumpers discover a man who was stabbed with a souvenir key chain soon after he apparently proposed to a woman on the bridge with a message displayed in lights on a nearby building. In the second case, the badly beaten body of a young heiress is found in her penthouse apartment. Meanwhile, Mac begins a relationship with a new medical examiner (Claire Forlani).
Three women dressed as Holly Golightly from “Breakfast at Tiffany's” rob a jewelry store and one of the managers is killed during the heist when a shotgun discharges. Across town, a mummified body is discovered during an old building's demolition. The corpse turns out to be the missing wife of a city councilman. Even though the autopsy concludes she died of natural causes, Mac believes she was murdered.
Mac and Stella work on the case of a marathon runner who dies during a race in Central Park. They discover that the victim was poisoned and had frostbite on his face, even though the temperature outside is in the 90s. Across town, Danny and Lindsay investigate the murder of a 23-year-old model, the face of a promotional campaign to launch a new brand of vodka, after she is stabbed to death during a party. Also, Danny gets upset with Lindsay when she stands him up for a dinner date.
Mac and Stella investigate the murder of a college student found decapitated, her body hung upside down from a ceiling fan. The grisly crime occurred during a sorority party and most of the witnesses are too drunk to remember anything. Later, another victim is found impaled on a tree in Battery Park, his eyes gouged out and two railroad spikes inserted into his head. Both victims were wearing unique shirts that contain hidden codes that could provide clues to the killer's identity.
A young punk rocker is found beaten to death in a Queens alley just a few blocks from where she recently finished performing in a show with a group called the Suicide Girls. Over in Rucker Park, a basketball phenom is discovered dead on an outside court a day after he defeated a professional player in a one-on-one game that embarrassed the NBA star, known for his violent outbursts.
A young hotel concierge falls to her death from a balcony and is impaled on a statue shortly after an ugly incident with a popular model participating in a rooftop photo shoot. While Mac and Stella investigate the case, they hear gunshots coming from a nearby building and discover the shots came from a penthouse loft. When they enter, they find a woman standing over two dead bodies, one of them her husband. The woman claims the other victim was beating her husband, so she shot the man.
A young woman dies after she starts bleeding from her eyes, nose and mouth while partying on a subway train, and Mac believes she may be the victim of a biological attack. Later, Mac learns that one of his investigators knew the victim. Across town, a wealthy playboy is found dead in an indoor pool in his penthouse suite. The probe reveals the man was murdered and that he had fired his maid two days earlier.
A professional paintball player is gunned down after he enters a warehouse where huge balloons used in the Thanksgiving Day Parade are located. He was playing a paintball game with a rival, who is now missing, when he was shot. The investigation reveals the murder may be linked to illegal drugs and a cop may be involved. Also, Stella fears she is being stalked, but when Mac chases down the suspect he gets an unexpected surprise.
A 19-year-old woman is murdered in her bed at the hospital where she's being treated following a car accident she caused while driving drunk. Mac investigates and believes the crime may be a mercy killing. The murder takes place in the hospital where Hawkes once was a leading surgeon. As he investigates the case, old wounds are opened up between Hawkes and his former boss, the chief of staff.
A wealthy Throggs Neck father is murdered in a new, expensive car he was about to give his daughter for a 16th birthday present. While searching the car, Lindsay is bitten by a cobra hidden inside. In Tribeca, a man who raised racing pigeons is murdered. His body is discovered after a parachutist, who was advertising an upcoming sporting event, dies because his open parachute is pummeled by dozens of dead, blood-covered pigeons that mysteriously fall from the sky.
A black man wearing a green hooded sweatshirt robs a Greenwich Village bar and guns down a bartender in the early morning hours. Soon afterward, a suspect matching the killer's description is arrested. Unfortunately, the suspect is Hawkes. Mac's team is immediately pulled from the case, but that doesn't stop Mac from trying to discover the truth. Also, a man is found dead in a Times Square peep-show booth. At first, it appears the man overdosed, but Stella believes he was murdered.
A 19-year-old deaf woman is gunned down in her parents' house. Lindsay arrives at the scene, but quickly leaves and later opens up to Stella about a dark incident in her past that continues to haunt her. Elsewhere, a 16-year-old skating star is murdered while practicing at a local rink, but Stella believes another skater, a national champion, may have been the intended target.
A well-heeled man is found dead in a vacant apartment, but the evidence suggests that the victim may have been killed by someone he kidnapped. In Central Park, a man's body is discovered stuffed in a shopping cart. The probe reveals the dead man was part of a bizarre race that uses shopping carts and that his team was sabotaged by other participants.
A female impersonator who performed at a party in a ritzy hotel is found dead in a men's room stall. He was drowned in the toilet. The investigation reveals the victim confronted a congressman at another hotel event shortly before being murdered. Across town, a man's body is found inside of a city salt truck. Also, Lindsay is asked to testify in a multiple-homicide trial in Montana. She was the only witness to the murders of four of her friends.
A Fifth Avenue security guard is gunned down in the dressing-room area of a ritzy clothing store and the chief suspect is a professional shoplifter (Nelly Furtado) who steals for personal clients. In Queens, a college student is found dead in a hedge maze and the investigation reveals the victim was working to expose a secret society on campus. Mac believes members of the group may be responsible for the murder.
A woman is found floating in a bathtub in a luxury apartment, but there is no initial evidence of how she died. The investigation reveals the victim was in the apartment of a man who took out a restraining order against her six months earlier. Across town, a music mogul is murdered in his penthouse. The victim's sister reports the killer is an intruder who has struck twice before. While collecting evidence, Stella accidentally cuts herself with bloodstained glass that may be infected with HIV.
A man is found shot dead in a rundown Rockaway Beach house under a pile of money. Outside in his backyard is an ark that contains animals and eight people. The investigation reveals the man spread the belief that the world was ending and charged people to go on his ark where they would be saved. Back in the city, a man dressed as a giant cigarette to protest a tobacco company is found dead on the street. Also, Stella tells Mac that she was exposed to HIV when she got cut at a crime scene.
A woman is found sawed in half inside a magician's wooden box onstage in an abandoned Times Square theater. The investigation reveals the victim worked for a famous illusionist (Criss Angel) who was performing outside when the murder occurred. In Montana, Lindsay testifies in a murder trial and struggles to recall a multiple homicide she witnessed when she was 14 in which three of her friends were gunned down inside of a cafe.
Mac and Stella must hurdle diplomatic road blocks to investigate a murder at the U.N. when a part-time translator is poisoned to death during a French Revolution-themed fund-raiser. Deputy Inspector Gerrard won't allow the CSIs to examine the body until all diplomatic clearances have been met. Across town, a chef is stabbed to death with a large corkscrew on the opening night of his restaurant and a live jeweled cockroach is found inside of his mouth.
The CSI members enter the world of genetic testing after a body is stolen from a coroner's van. Also, a man wearing medieval armor is impaled with a lance and another man is stabbed to death with an ice pick.
Alleged serial killer Clay Dobson (Joey Lawrence), whose conviction rested on his confession to a police officer, is set free after Mac arrests the cop in question. Soon, a murder victim turns up and Mac believes Dobson is responsible.
Stella becomes a murder suspect in a Philadelphia cold case when Det. Scotty Valens (Danny Pino) visits the lab and tells her that her DNA matches the evidence. Meanwhile, Mac's career is jeopardized when an internal investigation is opened against him.
Tennis legend John McEnroe is suspected of murder, despite a solid alibi, when evidence and witnesses all point to him as the culprit. Mac's investigation leads to a political firestorm that threatens to end his career.