CSI: Miami - Season 4

The team must find the connection between the two crime scenes; the killing of a drug dealer and the rape of a well-off family's housekeeper who happens to be pregnant.

When a rich family is trapped on a burning yacht in shark-infested waters, the CSI's must investigate how it happened.

The CSIs must investigate the dark side of Miami's nightclub scene when a teenage tourist goes missing. Sara Jennings was on her way to the Bahamas via Miami for a class trip when a wild night of partying, drinking and sex got out of control. Now, the CSIs must discover who she was with and what happened that night in order to find her. Meanwhile, Horatio's past in New York City resurfaces when an old unsolved case lands on his desk.

Horatio and the team are trying to figure out how to free an innocent young man after a harsh interrogation with Frank Tripp sends him to jail.

Three suburban housewives on a girls' weekend in Miami are the prime suspects when the hotel's handsome pool boy is found murdered. When Horatio is tipped off that his team is facing a surprise efficiency review, he must trust Calleigh, Eric, and Ryan to work together to find the killer. However, when they independently follow the evidence, each discovers that their analysis points to a different killer.

The CSIs must race against time when all evidence in a murder case points to Horatio. When a murdered woman is discovered, Horatio admits that he was seeing her and that he was the last person to see her alive. Although the evidence logically points to Horatio as the killer, our CSIs must now dig deeper to find the real killer and learn who would have the motive and the method to frame him.

A crossover episode that concludes on CSI: NY (episode 2.07 "Manhattan Manhunt") begins with a convicted serial killer who escapes after sabotaging an airplane that was flying him from New York to Miami, where he allegedly buried a body. After fleeing the crash site, the man goes on a killing spree and abducts a college student. Mac Taylor arrives in Miami to help Horatio and the team track the killer since Mac originally arrested the man in New York. The episode ends with the killer revealing that he's in New York, forcing Mac to return to New York to arrest him with Horatio coming along to help him.

The CSIs are called out to investigate the murder of a young woman who was about to sign her divorce papers. Soon the husband turns out to be the ideal suspect. The only strange thing about the case is the murder weapon: a nailgun. However, things become personal for the team when Ryan is attacked and left injured after being shot in the eye with a nailgun while revisiting the crime scene.

Eric finds himself in the middle of a robbery while at the bank. The team soon learns that the bank robbery is part of video game called Urban Hellraisers that is being played out in real life. To stop them, Ryan must play the game and figure out the robbers' next move before another crime happens.

A drug lord is gunned in his Coconut Grove mansion and a suspect arrested at the scene claims he sells marijuana to Delko. Stetler, from Internal Affairs, investigates and the case quickly gets personal when Horatio gets involved. As for the shooting, the CSIs learn that two gunmen may have been involved. Also, Calleigh makes a major decision concerning her job.

Horatio hunts for the man responsible for a brutal rape on a woman years back, after new DNA testing technology finds the convicted rapist innocent. Alexx and Eric investigate a doctor whose patient died from toxic shock after an appendectomy.

The CSIs investigate the brutal murder of a man who was learning how to pick up women at a hot nightclub. Meanwhile, Horatio tries to help out Marisol, Delko's sister, who was arrested on drug charges.

The Mala Noche strike again and it's up to the CSIs to bring them down once and for all. Also, major secrets are revealed about the characters and their love lives.

When evidence shows that a series of murders is linked to organized crime, Horatio and the team are instead lead to a pair of film students who have screenplay that contains the details of the crimes. Meanwhile, Ryan learns that his eyesight is getting worse after he was attacked in "Nailed" and as such, it might jeopardise not only his career as a CSI but also his future at the crime lab. The episode ends with Ryan furiously pounding on his locker door as Horatio silently looks on from a distance.

When Horatio's nemesis, Walter Resden targets someone from their past, Horatio tries to stop him. Also Delko's relationship with Natalia is tested when she thinks she may be pregnant.

Alexx's DNA is found throughout her neighborhood where she is suspected to be responsible for the death of a convicted child molester. The CSI team soon learns that the mindset of the neighborhood could lead to any of the community wanting the man gone. The team must find out who the real killer was to clear Alexx.

From what appears to have been a horrible car accident that claims the life of a woman actually turns out to be a murder case. The evidence turns up more information and another body. During the investigation Natalia confesses a secret history of marital abuse in order to help the case to be solved.

The Miami-Dade district attorney loses a highly publicized murder trial in which a husband is accused of killing his young bride and then dumping her body in a lake. However, the woman's body is recovered after the trial concludes, and the 'double jeopardy' clause precludes the husband from being tried again. Now, as the CSIs fear that justice may not be served, new evidence suggests that the husband may have actually practiced on another victim first, and Horatio believes that CSIs may be able to get the husband retried under different grounds.

After a group of wealthy young women's cars are stolen from a luxury day spa, evidence leads the CSIs to believe that this is a part of a much larger car chopping scam and each of these women are being targeted for a home robbery. Matters become worse when Horatio discovers that Marisol was also at the spa during the robbery and he becomes protective of her now her life is threatened. Meanwhile, Ryan must deal with the consequences of freezing during a raid on the chopshop.

The CSI team must try to find out who is trying to kill a young couple (introduced in episode 86) who are released from prison. The couple, who become a Bonny and Clyde type "media darlings" soon discover that not everyone regards them as such. Calleigh must work with an ex-friend to help solve the case.

The CSI team must locate a woman who has been kidnapped and dialed a wrong number on her cell phone. To try and locate her the team must first figure out who the kidnapped woman was trying to contact in the first place. Meanwhile, Marisol has a difficult decision to make and Horatio helps her. Natalia is surprised when Ryan asks for Delko's permission to take her out on a date.

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

During an A-list house party, an heiress is found electrocuted in her own bathtub. The list of suspects includes her musician boyfriend, her assistant, and her main modelling rival. Delko learns that Horatio and Marisol are soon to be married and has mixed feelings about their wedding.

The Mala Noche gang trial is stopped when the defendant escapes with the help of a fake witness and a gunman in the audience. Delko finds that a beautiful but disturbed ex-lover is stalking any woman who he is now close too, including his sister. When a hit is ordered by the Mala Noche gang on Horatio, Marisol however is the one who is critically wounded by a sniper's bullet and later succumbs to her wound and dies. When the gunman is found, Caine and Delko both go vigilante in their desire to see justice done.

Horatio and Delko search Miami to bring down the Mala Noche gang once and for all after the murder of Marisol. Further, after another Mala Noche related shooting, Officer Aaron Jessop is killed by a hand-grenade booby-trap at the crime-scene. The quest to end the crime-spree is jeopardized when the Feds, led by Agent Glen Cole, raid the CSI lab searching for missing cash evidence, based on an unknown tip. Tensions rise and the mole is finally revealed as Natalia Boa Vista, although it is the assistant SA, Monica West, with assistance from her fiance, Treasury Agent Peter Elliot, who is revealed to be behind the missing money. The eventual capture of gang leader Diego Riaz brings additional problems, as he strikes a plea bargain and is deported to Brazil - leaving Caine and Delko on a new mission seeking justice.