In the first part of a crossover with CSI:NY, Mac Taylor comes to Vegas to surprise his girlfriend, Christine, and to spend some time with his old friend, Russell. To their surprise, they find Christine's hotel room destroyed, with traces of blood and other evidence pointing to foul play, but no sign of her. Together, and with some help from the CSIs, Russell and Mac follow the evidence and try to locate Christine, only to hit dead end after dead end. Eventually, they discover that James Boyd, a manager at Christine's restaurant in New York, set up a fake business trip to Vegas in order to retrieve diamonds to pay off a gambling debt. Boyd left Christine in NY with his brother, but the man who wants the diamonds has kidnapped both of them and plans on killing them. Left with no other choice, Russell agrees to accompany Mac to New York to help him find Christine...

Meanwhile, the other CSIs investigate the murder of Jack Davari, a local wine collector who was murdered and stuffed into a wine barrel. Initially, it appears that Davari was killed by the heir to a famous French vineyard over a business.