CSI: NY: Season 9

After his friend, an FDNY firefighter, dies in a suspicious fire he responded to, Mac discovers similarities between that fire and a string of arson cases dating back fifteen years and decides to risk working with a pyromaniac ex-arsonist known as Leonard Brooks (Rob Morrow) to uncover the mastermind.

The CSIs rush to stop serial arsonist Leonard Brooks after he begins using fire against people from his dark past. Meanwhile, another detective, Jamie Lovato (Natalie Martinez), transfers to Homicide from Narcotics.

Mac and Jo travel to San Francisco in the search for a missing girl after finding photographs of her supposed dead body beside a male victim.

The CSIs search for a shooter when Lindsay is injured during what appears to be the attempted murder of a political candidate, and the events in the aftermath lead to a child's death.The first half of the episode has no dialogue, just music from punk rock band Green Day's new albums: ¡Uno!, ¡Dos!, and ¡Tré!. Featured songs include "Stop When the Red Lights Flash", "Amy", "Nightlife", "Kill the DJ", and "The Forgotten".

The cold case of missing boy Tommy Lewis gets reopened when the main suspect in the disappearance is murdered. The team now has to open old wounds and sift through this tightly-knit neighbourhood full of people with reason to kill the suspect. Meanwhile, Jo becomes curious about Mac's problem with words, and her ruffling leads Mac to warn her to stay out of his personal business, however Mac apologizes to Jo in the next episode. Flack has a day off and spends most of it dealing with family issue

The CSIs investigate a twisted fairy tale when a woman in a ball gown is found at the bottom of the pond outside Belvedere Castle in Central Park.

The latest victims in a series of murders leads the CSIs to believe the killer is playing a real life game of Clue. Meanwhile, after she's been pranked on in the lab, Lindsay investigates to find her prankster. Plus, Mac finally tells Christine about his speech Aphasia problem.

The team's latest case leads them into the world of performance enhancing drugs. Meanwhile, Lindsay travels to Montana for the execution of Daniel Katums, the convicted murderer of her childhood friends.

Detective Lovato's past as an undercover officer tangles up with her present duty when one of the gang members she ingratiated herself with and developed feelings for turns up tortured and killed.

The co-owner of a popular bar is found dead. Mac follows Christine's advice to tear up his to-do list and relax on his day off. On his day off Adam visits his father, who has Alzheimer's and is in a care home, trying to get his father to acknowledge him.

The CSIs are confronted with a puzzling mystery when two different victims are linked by the same unusual weapon, a gun created by a special type of 3D printer.

When an off-duty NYPD officer dies during a robbery, the CSI team interrogates the main witness to determine if he was a bystander or if he was somehow involved.

The CSIs investigate when a masked man is found at the bottom of a notorious skyscraper known for its history of mysterious deaths. Meanwhile, on her day off Jo runs into a stranger with a surprising link to her past. Lindsay tells Danny she is pregnant and the team reveals that they were betting on whether Lindsay was actually pregnant or not.

The CSIs investigate when a pizza maker is carjacked. The investigation leads to something far more sinister than they anticipated.

D.B. Russell heads to New York to help Mac find Christine's kidnappers before it's too late.This episode concludes a crossover with CSI: Crime Scene Investigation that begins on "In Vino Veritas".

Three separate homicide cases relating to romance are solved. In "Love for Sale" Danville and Lovato respond when Theodore Hart suffers death-by-champaigne. In "Love is Blind" Danny and Hawkes investigate Bernard Chandler's death-by-chocolate. Mac and Flack must find out why Jeremy Howser was shot through the heart "In the Name of Love." Afterwards, team members celebrate Valentine's Day, each in their own ways. Mac and Christine meet at a restaurant where Josh Groban is performing; Don surprise

When a patrol officer shoots an unarmed man after a jewelry store robbery, a mob forms in front of the precinct. The team struggles to figure out the truth quickly, but they are hindered because Mac, Flack, and the officer are trapped in the station. Later, Mac asks Christine to marry him and she accepts.