CSI:NY picks up where we left off, with Shane Casey holding Danny and Lucy hostage; Lindsay kills Shane Casey, and five months later receives medal of honor for protecting her family. With the entire CSI team at the ceremony, Jo Danville, new CSI, enters the empty crime lab and nearly stumbles over a dead body--a young woman who had been stabbed to death. Our CSI's track where the victim was stabbed and I.D the victim as an intern working in the architectual firm on the floor below. The evidence presents a curious picture as the building's security system was tampered with and shut down for an hour the night of the murder, suggesting a planned attack, however, everything about the murder suggests it was spontaneous. The blood evidence at the scene gets a hit in CODIS and leads them to the head of the architectual firm, Theodore Westwick, who was attacked the same night as the murder several blocks from the building. The team tracks down the alleged attacker, Alex, and Jo gets him to admit that he was present at the time of the murder but didn't do it - Westwick did. Alex shutdown the security system to rob the firm that night and witnessed the murder in progress. Westwick saw Alex and ran him down, trying to kill him, but Alex fought him off. Westwick was having an affair with the victim and she got pregnant. When they met that night they argued because she wanted to keep the baby. He knew that would ruin his marriage and the fabulous life he built so he killed her in a fit of rage.
Even though it's only Jo's first day on the job, she manages to impress everyone on the team with her intelligence and skills. Lindsay is struggling to come to terms with shooting Casey and the turmoil her family has been put through.