When a couple snatches a baby, Sophie Walsh, away from her mother, Jill Walsh, and disappears in the resulting chaos, the CSIs are called in to help follow the evidence to find Sophie. The case takes a turn when a DNA test proves Sophie's biological father, Brad Garland, is not Jill's husband, but instead a neighbor who Jill had an affair with. While Brad denies knowing Sophie is his, the CSIs find evidence that proves Brad hired someone to kidnap his daughter. But when the man he hired disappears with the Sophie, the CSIs have to race to find the kidnapper before he sells Sophie to a higher paying buyer in another country.