The two young owners of a city bar are gunned down after hours and another man is wounded in the attack, which was allegedly committed by a masked gunman. Meanwhile, Calleigh's dad announces he is now a public defender and needs her help with a murder case in which a woman allegedly stabbed her boyfriend to death in his car with a screwdriver.

A young woman is attacked by a shark and later dies, but it's discovered that she was shot first. The case becomes even more difficult for the CSIs when one of their coworkers becomes a leading suspect. The dead woman worked for a private-investigation agency that specializes in luring and entrapping married men suspected of infidelity.

A security guard is found dead after shots ring out at a rap star's concert and the CSIs must investigate. Rap star 10-Large won't talk to the police regarding the murder or why someone would try to kill him. But when evidence suggests that perhaps 10-Large's bodyguard was the intended target, the CSIs must look into the dangerous world of personal security. Meanwhile, Alexx gets the shock of her life when a supposed cadaver from a recent car accident wakes up in her morgue, suffering only from hypothermia.

An adult film actress is found strangled in the park and the CSIs must find the killer. Blood and human tissue are found under Ashley Anders' nails and the DNA matches that of the CEO of the company that distributes her films – and he's a registered sex offender. Also, Calleigh discovers his answering machine audiotape on which he makes a threat against Ashley. However, there is an accident back at the lab with this crucial piece of evidence and Delko was the last person to handle it. Now, IAB's Rick Stetler is put on the case, much to Horatio's dismay, as the CSIs try to uncover further evidence in order to find the girl's killer.

After a large yacht slams into a major Miami bridge, the team finds that the man steering the boat was shot and killed before the accident. The victim's wife reveals that their son had been kidnapped and her husband was handing over the ransom – three million dollars worth of jewels. But when the team learns that the jewels were fake, the investigation leads them into a dangerous situation at a jewelry shop that may contain crucial evidence, where Horatio must face the unimaginable when one of the team is killed in the line of duty.

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.

Horatio's life is changed forever when he learns important information about his deceased brother. Horatio must now figure out what to do with this information about his brother, Raymond, and whether or not to tell Yelina. Meanwhile, the team investigates when a woman is murdered at a crowded bar after she's approached by a female employee of a service that helps men pick-up women. Also, when Delko loses his badge after some reckless behavior and it's used in a crime, he must locate the badge before it's used again.

A cruise ship that is docked in Miami is the scene for a double murder. The team investigates the long list of potential suspects but soon find that the list is dramatically decreased when the CSI's find a large amount of money is missing from the victim's stateroom. Horatio and Marisol's relationship evolves.

The team is sent to investigate the death of a local celebrity, who is found murdered in her bathtub. The list of suspects includes her musician boyfriend, her assistant and her rival. The search for a young abducted girl is triggered, and Horatio tells Delko of Marisol and his plans.