In reverse motion we find out where the body of a pretty young woman had been the night before she ended up being dumped in Central Park.
When the team shows up to investigate the scene, they wonder if her murder is related to another recent homicide that resulted in a young woman's body being dumped in the park, Macy Martinez. Both bodies were strangled and signs say they have they same killer.
Josephine shows up on the scene and orders Mac go home and get some sleep because he's been working cases back to back.
A stamp on the victim's wrist indicates a club she went to recently. Not only that, but a trace of rare purple paint under her fingernail leads the team to search for a Manhattan art collector. When the team show up at his apartment the place looks like the crime scene had already been processed.
Soon the team finds out that a private investigator had worked the apartment. When the apartment's owner, Charles Martin, returns, he gets arrested and admits to killing two women. But there's evidence of a third murder. Eventually the team learn that she was killed by the private investigator's client. The husband eventually admits to her murder.
In a parallel plot, an ex-con recently released from Riker's Island goes after Mac, who sent him to jail.