After an exhaustive day, Catherine stops by a bar where she has a fling with another customer. As she is leaving, he gives her his number on the bar's match box. Later on that night, Grissom calls in for a favor as he is short on staff. A woman was murdered. Prior to her death, she was seen with the same man who was hitting on Catherine in the same bar. A similar match box with a phone number inside, found on the victim, further points to this man as the main suspect.
At the end of the shift Catherine goes for a drink in a local bar, Highball, where a guy tries to pick her up. They go out to her car in the parking lot and start making out. She stops him and declines to go any further, saying she needs to go home. Angered, the man turns aggressive and nasty. A brief struggle between them ensues, and Catherine ends up hitting the side of her face on her car door. Later that night, after returning home, Catherine gets called out to support Grissom's team. She asks her mother, who is sleeping on the couch, to take care of Lindsey. Her mother admonishes her for drinking and inquires about the bruise on her face.
At the crime scene, a girl has been found shot close-range in the head, her body in the middle of a parking lot with her face covered by her jacket. As they investigate it turns out the victim was at the same club Catherine was, at about the same time. Sara and Catherine look through the victim's personal possessions she had on her when she died, and they find a matchbook that was the same matchbook the aggressive man had given Catherine at the bar.
When another body is discovered in similar circumstances they eventually pull in a suspect who turns out to be the same man who tried to pick up Catherine, a local attorney named Adam Novak. This leads to questions about her private life. Eventually it is discovered that the first victim's ex-boyfriend had been stalking her and killed her out of jealousy, later killing the second victim to frame Adam from the bar.
Grissom expresses his displeasure at Catherine's involvement, professing not to have a private life for this reason.