Jo and Mack arrested a pickpocket outside the unveiling of a holiday window display. As the store window was revealed so was the dead body of the department store's manager, Richard Grossman.
Evidence at the crime scene showed that the murderer was injured in the struggle, and Jo and Danny followed a blood trail that proved that theory. Blood found on the pickpocket's jacket along with his testimony led the CSIs to Alena Maybrook, an assistant manager at the department store. Jo recognized her from that evening and discovered her in apparent shock in a park where she had previously seen her.
Alena did not say anything while in police custody. Evidence taken from under her nails and wounds discovered by the paramedics led the CSIs to believe Alena was attacked and may have killed the store manager in self defense. Flack, however, found evidence that the murder may have been premeditated since Alena had a one way ticket to Aruba.
Further evidence left at the crime scene took Danny and Flack to question Alena's fiancé whose fingerprints and burnt skin were found at the crime scene. Alena's fiancé admitted he had a confrontation with Grossman when he was fired, but had not seen him since. He also revealed that he and Alena were no longer engaged.
The wounds on the body of the Richard Grossman confirmed that he had attacked Alena, and a camera was found that contained a video of Alena stealing from the department store. Before Jo and Mack could go and arrest Alena, Lindsay informed them that Alena was dying.
Jo met with Alena in a park, and Alena related her story. She had extorted money from the store in order to give it back to hard working employees who were going to lose their jobs with no notice. Richard Grossman had caught her and was using the video to blackmail Alena into doing sexual favors for him. Alena wanted to stop the blackmail and accidentally killed Grossman trying to get away from him.