The CSIs uncover a complex counterfeiting operation after a bellboy is found murdered at one of Miami's hottest hotels. The luggage that the deceased bellboy had been loading, as well as a heist of a special paper that money is printed on, leads the CSIs to uncover a complex counterfeiting operation. It's cruise season in Miami, which means that the population of Miami swells, giving the team even more suspects to the murder. Meanwhile, Calleigh must investigate when a woman goes missing, and is later found dead, after she and her husband attend a hot and flirty "friction" party.

When the CSIs find a woman swallowed whole and killed by a gigantic snake, they uncover a covert drug smuggling operation. Evidence leads Horatio and the team to a drug smuggling operation where large snakes are suspected of be being used to bring illegal drugs into the country to avoid detection by customs. However, when Horatio finds that Clavo Cruz, a nemesis of Horatio's who hides behind his diplomatic immunity, may be behind the operation, the team must find a legal way to put the criminal behind bars. Meanwhile, Wolfe must find the truth when two women each claim that they are the real victim of identity theft and the other is the culprit.

Evidence leads the CSIs to believe that someone started a massive fire in the Everglades in order to cover up a murder. Local prisoners are brought in as free manpower to help fight the wild fire in the Everglades. However, when a serial killer escapes the scene, Horatio must track him down before he strikes again. Meanwhile, the body of a local college student is found shot to death and the fire has destroyed the crime scene and the evidence. However, when the team uncovers an illegal moonshine operation and homemade ammunitions in the vicinity, the CSIs uncover the real reason why the boy was out there.

Someone uses a laser light to blind a pilot and bring down a jet, which carries $1.2 billion in checks to be delivered to banks on the eastern seaboard. The crime scene evidence reveals a victim, a young fundraising socialite, who was inside the plane but killed prior to the crash. Now, although the team has little to work with since the victim's wealthy family is opposing an autopsy, Horatio must follow the money trail. Meanwhile, Calleigh works on the case with her ex-boyfriend, Detective Hagen, and their romantic history could cause problems for both of them.

An IRS agent is killed while trying to repossess a delinquent taxpayer's yacht soon after the CSIs discover a second IRS agent shot to death. Now, just when everyone has a reason to detest the IRS, Horatio must find who is behind what could possibly be a series of murders right before tax day.

After a bitter custody battle, shots are fired outside the courthouse. Bullets fly and the target is the little girl's mother. Horatio goes after the father, who he suspects may not be the girl's biological father after all. However, when the mother's shady past is uncovered, the team finds that she has a lot of enemies who would like to take a shot at her. Meanwhile, Calleigh's father returns to the crime lab for her guidance but for an unexpected reason.

An axe murderer on death row is given a stay of execution just moments before it was to take place, on the grounds that there may have been tainted DNA analysis used at his trial. Now, without using any DNA evidence, the team must race against time and reexamine all of the physical evidence in the case, just as they get a call on a new double murder that looks suspiciously like the case they're working on.