The third season finds the team in search of new beginnings as Det. Flack comes back to the job after slowly recovering from his injuries and Mac secretly begins dating again after the death of his wife. Mac finds companionship in a co-worker, which presents a unique challenge as he tries to figure out the professional and personal connotations of his private and public lives intersecting.
When a man is found dead on the Brooklyn Bridge and the only evidence is his marriage proposal displayed in lights on a Manhattan high-rise and a souvenir key chain as a murder weapon buried in his chest, the team comes together to find the person who may have brutally rejected his offer.
The CSIs investigate a jewelry store heist where three women dressed as Holly Golightly pull off a major robbery with innocent shoppers hurt in the process.
When a runner drops dead in the middle of a marathon and the cause seems to be carbon monoxide, Mac and Stella can't reconcile how someone would be poisoned in the middle of Central Park.
Mac and Stella track a serial killer who uses the codes and stories found on a series of trendy t-shirts as inspiration for his grisly murders. Edward Furlong guest stars.
An 18-year-old's dream of becoming a SuicideGirl ends tragically when she is brutally murdered after performing in one of their shows. Missy Suicide guest stars.
The CSIs are suddenly faced with two crime scenes when, while investigating the murder of a hotel concierge, they hear gunshots fired across the street and find a woman clutching a gun over two dead bodies. Dedee Pfeiffer guest stars.
A young woman is found dead on the subway.
The investigation into the death of a professional paintball player becomes complicated when the team's prime suspect goes missing and the evidence possibly implicates one of their own.
When a woman is murdered in her hospital bed after surviving a drunk driving accident that she caused, the CSIs work to uncover the killer as their list of suspect grows, Mel Harris guest stars.
While investigating the death of a base jumper, Mac, Danny and Det. Flack discover the body of a trainer found brutally murdered on his roof and whose pigeons where poisoned.
When a bartender is shot in cold blood after a robbery, the CSIs are shocked when the prime suspect is Sheldon Hawkes. Edward Furlong, Claire Forlani, John Kapelos and Emmanuelle Vaugier guest star.
When a 19-year-old is shot while protecting her baby sister's crib, Mac relies on the teenager's family, who are all hearing impaired, for vital clues that will help him track their daughter's killer.
A man found dead in the snow with a price tag hanging from inside his stomach leads the CSIs to the annual Idiotarod race where young New Yorkers in creative costumes race decorated shopping carts from Brooklyn to Manhattan as if they were dog sleds.
When a transgender showgirl is drowned in a rest room at a five-star hotel, the CSIs investigate if the killer was surprised to discover the performer's secret and committed murder as a result.
While investigating the death of a college student found dead in a Queens park, Mac, Sheldon and Det. Flack discover a secret college society that may have been behind the victim's murder. Nelly Furtado guest stars.
When a music industry mogul is murdered in his high-end penthouse apartment, Mac, Stella and the team must rely on the crime's only witness, the victim's sister, to solve their case.
The CSIs investigate a bizarre murder where a man named Noah is found buried under a sea of cash after being shot in his home and with a 20-foot ark full of people and animals in his backyard.
When world-renowned illusionist Luke Blade brings his act to the streets of New York and two of his crew members are found dead in ways that mimic his illusions, Mac and the team wonder if his tricks have become reality.
Mac and Stella face diplomatic road blocks while investigating the murder of a member of a young girl's entourage of professional handlers who was killed during a French Revolution-themed fundraiser at the U.N.
The CSIs are faced with two bizarre murders and a case that leads them into the world of genetic experimentation.
Mac's arrest of a police officer allows an alleged serial killer to be set free, forcing Mac to take matters into his own hands.
Stella is a murder suspect when her DNA matches the evidence in a Philadelphia cold case. Mac's career is put in jeopardy.
The CSIs are puzzled when evidence and witnesses point to John McEnroe as their murder suspect despite his air-tight alibi, and as Mac's investigation causes a political firestorm, the team worries he'll be dismissed when they are asked to testify.
Following the largest drug seizure in city history, Mac, Stella and Hawkes are forced to save the lab when, in an elaborate heist, a drug lord and his crew descend upon the CSI's vault to retrieve their merchandise.