The body of a man involved in recovering sunken treasure is discovered pinned to the wall of his new cabin cruiser by a bloody spear fired from a speargun at close range.

A gas man is engulfed in invisible flames and dies during a qualifying race at the Grand Prix Americas.

A diamond broker carrying two million dollars in merchandise is murdered after his car is hit by another vehicle and he gets out to confront the driver. The only witness to the crime is a developmentally challenged man who says the killer is someone named Colton. Meanwhile, outside of town, Speedle and Delko investigate the death of a teenage girl discovered at a rest stop with a broken neck. Shortly after the victim is taken from the scene, her body disappears during transport to Miami.

Delko and Alexx are nearly burned alive when they investigate the death of a hunter found shot near a supposedly controlled burn in the Everglades. The fire suddenly rages out of control and traps them, forcing them to take refuge under a tarpaulin. Later, a second body is discovered, and this time it's a young woman who looks to have been beaten to death. After bite marks are found on the victim's breasts, Horatio is led to believe a sex offender is behind the attack – and the fire.

An 18-year-old girl is stabbed to death in a bathroom of a popular Miami nightclub. Horatio learns that the victim was an investigative aide working for Alcohol Beverage Control and was monitoring underage drinking. As Horatio interviews the club's owner, an unknown man drives by the club, sees that the police are there, and crashes his car while fleeing the scene. However, the case gets more complicated when they discover another murdered victim inside the car. DNA from the second victim's watch ultimately leads them to a day spa where the services may not be entirely legal. Meanwhile, Calleigh and Ryan work together to determine whether an insecure and underage teenager at the club that night had anything to do with the murder.

The team investigates a modern-day piracy off the coast of Miami after six bodies are discovered floating in the ocean tied together by rope. Horatio suspects that a ship was hijacked with some of the crew killed and then dumped overboard. Evidence suggests that other crew members might have escaped on a life raft. Using radar and GPS technology, the CSIs find survivors but their stories don't match. Now, Horatio and the team must learn what really happened out in the ocean as they find themselves investigating the seamy underbelly of Miami's militias and arms dealers.

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.

An extreme skateboarder and videogame tester is found dead on a half-pipe platform used to program extreme skateboarding video games. The CSIs discover that he was wearing reflective sensors when he was killed, so the motion-capture device used to produce these videogames recorded the murder as it happened, but not the murderer. Now the team delves into the highly competitive world of videogame programmers and testers to find the killer.