One of the most successful spin-off series in the history of television, CSI: Miami returns for a fifth series this fall. The show, reported by Reuters this year as the most watched television show in the world, returns this season with the continuation of an explosive story line that threatens to destroy Lieutenant Horatio Caine - and has already cost the life of someone close to him. If you've fallen behind in the fourth season of CSI: Miami, here's a short primer to bring you up to date with the world of Horatio Caine and his crack team of crime scene investigators. 424: Rampage After marrying CSI Delko's cancer stricken sister, Marisol, things are going swimmingly for Lieutenant Horatio Caine.

While she may have little time left, the couple are enjoying the time they have together to the fullest. That is, until Horatio gets caught up in the criminal trial of a leader of the sinister crime gang Mala Noche. When gang leader Raphael Sifuentes escapes from his trial Lt. Caine shoots his accomplice Jose Truillo dead, incurring the wrath of the Mala Noche.

In retribution for the killing the gang put out a hit on Caine's new wife, Marisol. Both she and Delko are shot by a sniper from a high-rise building. While Delko's wound is not life threatening, Marisol is seriously injured. While being rushed to hospital, Marisol's ambulance is ambushed by members of Mala Noche driving a black Lincoln. Caine leaps from the ambulance, firing on the car and taking out two hitmen while the driver, Memmo Fierro, escapes on foot. Meanwhile, Marisol's condition worsens due to the delay in receiving treatment, and she later passes away in hospital.

Caine and Delko succeed in tracking Marisol's shooter, Memmo Fierro, to the hotel at which he's staying. They drive him to an isolated spot in the Everglades, and Caine holds a gun to his head. Paralyzed with fear, Mierro reveals that it was Mala Noche member Antonio Riaz who ordered the hit on Marisol.

425: One of Our Own The season finale begins with the continuation of the search for Antonio Riaz, the Mala Noche gang member who ordered the killing of Marisol Delko. The CSIs are called to a murder scene at which 5 members of Mala Noche were gunned down, and it seems that the scene was Riaz' safe house. While clearing the scene, police officer Aaron Jessop triggers a booby trap - a grenade hidden in a barbecue - and is killed. It appears that Riaz wished to leave a surprise for Lt. Caine. The weapon used to kill the gang members, an AK47, is tracked to Rafik Ohmad, a weapons trader who did business with Mala Noche.

Video evidence of a trade between Ohmad and Riaz reveals the real reason Marisol Delko was executed - she was a witness to the deal, and was killed to ensure her silence. The CSIs also track down a phone number for Antonio Riaz, and while speaking to him he admits the real reason for the hit. He also boasts that there will soon be a "fireball over Miami" - leading Caine to surmise that Riaz purchased a surface-to-air weapon from Ohmad, and intends to destroy a commercial airliner. Meanwhile, an FBI investigation into the CSI unit stifles the team's work.

It seems that $12,000 cash went missing from evidence, and the feds were called in to investigate. It emerges that Delko's off-and-on love interest, Natalia Boa Vista, was an FBI mole sent to discredit the Miami Dade Police Department, but she insists that she didn't report the missing evidence. CSI Ryan Wolfe re-investigates the evidence and proves that the cash was stolen by someone outside of the department. In fact, the money was stolen by State Attorney Monica West in an attempt to discredit the department for her own political gain. Her fiance, Treasury Agent Peter Elliot, draws a confession from West that leads to her arrest. With time running out, Antonio Riaz is spotted by a police helicopter setting up a shot on an industrial estate near Miami Airport.

Arriving at the scene just in time, Caine takes out Riaz with two shots to the leg as he pulls the trigger on the anti-aircraft weapon. Resisting the temptation to kill him, Caine fires a shot close to Riaz' head to scare him into submission. The series concludes with the shocking news that Riaz cut a deal with the FBI, agreeing to inform on an Afghan terrorist sleeper cell operated by Rafik Ohmad in exchange for his extradition to Brazil, where he will most likely go free. On hearing the news, Horatio tells Delko to pack his bags: they are going to follow him. What's Next? We can expect an exciting start to the fifth season of CSI:Miami.

On arriving in Rio de Janeiro Caine meets with his sister-in-law Yelina, who fled there with her husband Ray and their son, Ray Jr, in the final episode of the third season. However, all is not well. Raymond has gone missing, and Ray Jr, now 14, has been forced to infiltrate the Rio underworld in order to track him down.

Little does he know that it may already be too late. So, how will this story arc conclude? Who knows? CBS are keeping tight-lipped on new developments in the fifth season of CSI: Miami. The only way to find out, then, will be to tune in.

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