During the ninth season crossover with "" Christine plans to attend a restaurant convention in Las Vegas and Mac decides to surprise her there. In "In Vino Veritas", he meets up with D.B. Russell whom he'd met previously at a forensics convention. They find Christine's hotel room trashed and eventually discover she was kidnapped by her restaurant manager James Boyd before she left New York. Mac and D.B. return to New York to find her in episode 9.15 "Seth and Apep" and Mac goes a little over the line to rescue her.