Horatio battles the FBI and U.S. Marshals as he tries to uncover why a woman was murdered at the side of a pool at a hotel. The investigation begins shortly after the woman is found dead from two shots to the head. The evidence suggests that it was a professional hit man, which is strange enough, but the case becomes additionally puzzling when the Feds and U.S. Marshals get involved. Plus, the murder weapon is linked to a cold case that was orinially investigated by Yelina. Meanwhile, Calleigh talks to her dad about his drinking problem after she's called away from work to drag him out of a bar.

The team investigates the deaths of two college students who were in Miami on spring break. The first is a teenage girl found dead on a beach with her neck broken and human bite marks on her legs. The second is a young man found in the bottom of a hotel swimming pool who apparently died before he hit the water.

An inmate at a massive Miami prison complex is stabbed to death in the prison yard. Shortly after Horatio arrives on the scene, a helicopter appears above the correctional facility. He immediately fears that the murder was a decoy to set up an escape. That's confirmed as three prisoners hop aboard the chopper and flee. As the investigation gets underway, the identities of the fugitives become known and a horrible realization sweeps over Horatio: two of the escapees are cold-blooded killers who already have their next victims picked out, and the other is a child molester who he recently put away.

Horatio investigates the murder of a model intentionally run down outside of a Miami hotel by a driver who fled the scene. When the evidence leads to a suspect, governmental red tape puts an unexpected twist on the proceedings. Horatio and Yelina begin to confront their feelings for one another.

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.

Horatio hunts for the person responsible for a vicious attack on a woman who was lured to a vacant condo and beaten with a piece of lumber.

A man and his wife are trying to drive out of a hurricane's fury when they strike and kill a man in the blinding storm. Horatio finds that the lack of impact wounds on the victim's knees suggest that he struck the car as opposed to the car striking him. Meanwhile, in a seemingly unrelated case, Horatio finds another victim of the hurricane impaled on a fence. However, as the CSIs uncover the scattered remains of the post-storm evidence, it seems that these two cases may have a deadly connection. Meanwhile, after Calleigh witnesses a man looting a house, she realizes that she's got another case on her hands when she finds his ex-wife inside shot to death.

Horatio is driven to find his brother's killer and protect the niece he never knew existed when a woman shows up with Ray's illegitimate child. The team explores a voyeuristic Internet site in connection with a stockbroker's murder.

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 young woman is thrown over the railing of a parking garage, but the investigation into her death uncovers evidence that she was killed before the fall and had likely been kidnapped. The victim's watch is traced to her boyfriend, who tells the detectives that she was a thrill seeker who was abducted during the course of an extreme kind of role-playing game. Meanwhile, Delko gets into trouble when he inadvertently interferes with a case after stumbling across a car-theft ring.

A celebrity photographer is found dead in his car following an accident, but Horatio believes he was murdered. The investigation leads to an A-list movie star who was caught in a compromising position in photos taken by the paparazzi.

Horatio and Speedle's case hinges on the testimony of a forensic-evidence enthusiast who stole a blood-drenched latex glove from the scene of the murder of a man who was stabbed to death with a butterfly knife. When Speedle tracks him down, the CSI wannabe is impressed by the ease with which Speedle was able to locate him, and the two begin to develop a slight bond when he shows up at the crime lab the night before he is set to testify. However, their relationship is cut short when the young man is found dead in his forensics-shrine of a home. Meanwhile, Delko and Calleigh probe the shooting death of a young woman whose body is found wrapped in a plastic garbage bag in a dumpster near the ritzy Miami club where she worked.

Josh Dalton, a hot, young reporter for the Miami Sun, witnesses the murder of his friend, a city councilman's aide, in Miami's drug district, the Golden Triangle. Josh, who was suspiciously unharmed in the attack, claims that they were only down there on a story, but Horatio believes that there's more to the situation. Later, another writer from the same paper is found shot to death inside the trunk of her car, which was reported stolen. Now, as the evidence rejects Josh's version of what happened, the CSIs find themselves entangled in the world of fast-paced journalism and learn that there is a dangerously fine line between the truth and what sells newspapers.

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.

The CSIs must find the killer after a young woman is pushed in front of a moving bus. Alexx finds a bruise shaped like a hand imprint on the victim's back, proving that she was pushed in front of the bus, and her boyfriend, Jay Seaver, is the prime suspect. When one of Jay's office rivals also turns up dead, Jay reveals that he has a psychotic stalker, Claudia, who he thinks might kill to please him. However, when Jay hires a lawyer to protect Claudia, Horatio suspects that Jay may be more involved than they thought. Later, a man's body is discovered down an elevator shaft in a nearby building, and there is evidence to link the victims to a common killer. Meanwhile, Calleigh's father seeks her help when he fears that he may have killed someone after a night of drinking, and Horatio assigns a new CSI, Ryan Wolfe, to the case.

E-mails and text messages trigger a mass gathering of students to perform a random task on a golf course. However, as the crowd disperses, the body of a high school student is found. The original message triggering the "flash mob" is traced to a high school senior whose father is a high-powered defense attorney. The case changes direction when Horatio and the team learn that the schoolmaster's daughter may have had something to do with the murder and evidence reveals that the victim was having an affair with his chemistry teacher.

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 wife of a famous baseball player is brutally killed in her home and her philandering husband is charged with the crime. The jury on the case, as well as the accused and his defense, visits the house to examine the crime scene, but when the lights are dimmed, as they were when the victim was killed, and then turned back on, the ball player is found dead with a meat clever in his back and a note that reads "guilty." Now, as Horatio and the team find that the husband's defense team tampered with the crime scene, they must examine the evidence to find the couple's killers. Meanwhile, Horatio gets a call from Yelina, who tells him that her son, Ray, Jr., is missing.

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.

A murder investigation takes Horatio and the team into the world of speed dating. Richard Laken is found killed by a tire iron outside a lounge following an evening of speed-dating. The team discovers his car is covered with acetone, which traces back to one of the female guests. She reveals that she dated Laken and he dumped her, so she doused his car with nail polish remover for revenge, but she didn't kill him. Now, when Horatio and the team learn that Laken recently witnessed a serious assault at a Miami Heat basketball game, they are on the hunt for two perps instead of one.

The CSIs must investigate when a pedestrian is killed after a man falls from a building and lands on him. Horatio and the team find that the victim found on the sidewalk is not the same man who fell from the building, but the unfortunate person he landed on. The CSIs discover that the fallen victim is in possession of a sex DVD involving a top Miami criminal judge and a woman with a sordid sex life. When the woman is found dead, the team must delve into the complicated personal lives of those in Miami's judicial system in order to find the killer.

When a woman is killed in what looks like a carjacking, the CSIs talk to her husband, the oldest of the three brothers who run their lucrative family business. However, when it is revealed that the victim had a gambling addiction that could have bankrupted the company, the team must follow the evidence to find the killer. Meanwhile, Alexx hires a recovering alcoholic as a body hauler and must investigate when he is accused of stealing from the dead.

When gang-related gunplay goes down in an emergency room, Horatio and the team must find the gang members responsible. The evidence suggests that an orderly in the hospital recognized the wounded gang member, who possibly killed one of the orderly's friends and alerted gang members to his location. However, the evidence doesn't match up and the CSIs discover that a cheating girlfriend, not gang retaliation, may be behind the shooting. Meanwhile, Ryan questions a mother in the emergency room after her story regarding her child doesn't add up.

During a routine traffic stop, a police officer is murdered and now Horatio and the team must track down the killer. The only witness to the murder is a civilian who was doing a ride-along with the officer, but who is now missing. Roadside evidence leads the CSIs to Missy Marshall, a teenage girl who was with the killer at the time of the murder. However, as the team searches for the civilian and the killer, they find that Missy may have been more involved with killer and the shooting than she is admitting. Meanwhile, Horatio and Rebecca's relationship is in jeopardy when they don't see eye to eye on a case.

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 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.

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.

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.

While investigating the murder of man hired to make dirty bombs that terrorists intend to set off in Miami, Horatio finds the bloody fingerprint of his brother, Raymond, who he believed to be dead. However, when Raymond's son is kidnapped, he emerges from deep undercover and the estranged brothers must work together to save the boy. Meanwhile, while processing a crime scene, an unknown assailant holds a gun to Calleigh's head and, after a deadly confrontation in her gun lab, she is left doubting that she can continue as a CSI.