As a huge tsunami heads directly towards Miami, a ten-hour warning gives citizens just enough time to evacuate the city. In the chaos, two people are killed in a parking lot and the evidence leads Horatio to discover a plot to rob a bank timed to take advantage of the evacuation. However, as the CSIs close in on the robbery already in progress, they find that it's a more elaborate crime than they previously thought. In the wake of the storm, Ryan and Alexx discover a body washed up from a local cemetery that may have a different cause of death than originally recorded. Meanwhile, Horatio suspects that Yelina is being physically abused by her boyfriend, IAB's Rick Stetler.

Horatio Caine calls Las Vegas CSI Ray Langston to come to Miami when a severed leg found in the Everglades is discovered to belong to a girl who went missing in Las Vegas a week earlier.

The crossover continues on CSI:NY S06E07 Hammer Down (II) and CSI: Crime Scene Investigation S10E07 The Lost Girls (III).