Danny and Mac have yet to get any leads on a cop killing when Danny gets an impromptu call from a young woman who claims she's got information about the case...

The case of a cyber killer, who appears to be targeting medical healthcare workers, turns personal when the suspect invokes the name of Mac's father who had died nearly two decades earlier.

When two bodies are discovered at the North and South ends of the city, Mac and the team deftly begin to navigate the trail of evidence left behind by the killer.

Incriminating DNA evidence contradicts the confession of a scorned woman claiming to have brutally murdered her cheating husband.

When an unidentified shooting victim turns out to be a rising star in the underground world of hip-hop dance battles, the CSIs turn their attention to a long list of rival dancers.

When a software company executive bleeds to death on a Manhattan street, the CSIs must delve into the wet and messy world of food "sploshing" parties - where groups of people experience food in an sensual way - to find his killer.

The Compass Killer is back, and adds yet another to his circle of victims -- but this time the CSI squad knows his name; Flack's alcoholism threatens to derail his career...

In the culmination of a multi-episode mystery, Mac and his team uncover the dark lair of a murderous madman, the Compass Killer. But as they race to save his fourth victim, the sunrise presents one final surprise that no one ever expected.

A frantic 911 call sends the CSIs into a vacant penthouse; however, instead of finding the caller, they unearth a nearly 100-year-old corpse and find themselves navigating their way through a booby-trapped house.

A reformed drug addict with everything to live for is found dead in an alley. The CSI's discover he was the victim of a premeditated plot.

The investigation of a brutal stabbing takes a dangerous turn when it's discovered that evidence at the crime scene was planted, which pits the CSIs against a trusted colleague.

When a beautiful star quarterback of the Lingerie Football League is found murdered in the locker room hot tub with traces of lidocaine in her system, the CSIs are called in to find out who wanted her dead.

When a young woman's body is found in Central Park, drained of blood and missing part of her ear, the CSIs jumpstart an investigation that takes them into the dark and mysterious subculture of vampirism.

Two days before a Grand Prix Race, when a racing legend dies in a car explosion on the streets of Manhattan, the CSIs discover that car tampering is the cause; however, the investigation leads viewers through the professional racing community and beyond.

The team investigates the particularly gruesome outcome of a 21st birthday where the party plans became all but anything worth celebrating. With just a few and not easy answers as their only lead in the case, the CSis are challenged to stretch their abilities to the limit.

It's St. Patrick's day, and all of New York City is ablaze with a hundred shades of green -- except for an abandoned warehouse in Brooklyn, where two corpses have left a tiny part of the city drenched in red...

When a woman linked to an unsolved murder case is found dead, the evidence and autopsy both suggest a suicide, but Stella is unconvinced and risks her life to pursue the case.

A death row inmate's final request brings Dr. Hawkes to a Pennsylvania prison and face-to-face with a tragic incident that he has kept secret for many years, just as a prison riot erupts and traps Hawkes inside.

When a slab of concrete starts bleeding in midtown, the CSIs' investigation takes them into the underground world of hardcore fighting, where men moonlight as 'weekend warriors' for the pleasure of a live viewing audience.

When Mac and Aubrey come across the scene of a 14-year-old boy who has been shot in front of his 12-year-old brother, it takes Mac's drive for justice to another level.

While Mac recuperates at home after being injured, he witnesses a mysterious briefcase exchange that leads to a murder, and unexpectedly brings him in contact with his former girlfriend, Peyton Driscoll.

The CSIs follow a trail left by Shane Casey and realize that he is targeting Danny, who is vacationing out of town with Lindsay and their daughter.