|Original Airdate||18 Sep. 2006|
|Previous Episode: One of Our Own|
|Next Episode: Going Under|
Rio is the first episode of season 5 of CSI: Miami.
Horatio and Delko travel to Rio to find Riaz, the man responsible for Marisol's murder. While there, Horatio meets Yelina and learns that his brother is back doing undercover work and may be connected to Riaz, for whom Horatio also suspects his nephew is working. Back in Miami, Natalia, now a CSI, helps Ryan investigate the beating death of a woman in Coral Gables.
Horatio Caine and Eric Delko arrive in Rio de Janeiro with revenge on their mind, intent on hunting down Antonio Riaz, the killer of Horatio's wife and Eric's sister, Marisol. Riaz haughtily taunts Horatio as he's released by Brazilian authorities who aren't convinced by the Miami DA's case against him. Horatio pays a visit to Yelina Salas, his brother Ray's wife, fearing that Ray is embroiled with the drug lord. His fears are confirmed, and worse, he learns his nephew, Ray Jr., might also be involved. Calleigh is at charge back in the lab, and she and Dan Cooper identify a substance on Ray's shoe that leads Horatio and Delko into a rainforest in the heart of Rio. It's too late for Ray--he's found beaten and barely alive. Horatio stands by helplessly as his brother passes away, and he vows to protect his nephew. Yelina uses a GPS tracker on Ray Jr.'s watch to locate the boy, but he's with Riaz and the drug lord spirits him away before Horatio can stop him.
Back in Miami, Ryan reluctantly accompanies new CSI--and former mole--Natalia Boa Vista on a case. Fanny Silver lies dead in her house, and suspicion falls on her husband, Carl. Natalia assures Fanny's son, Scott, that the killer will be brought to justice. Scott is certain that Carl killed his mother, but the real culprit proves to be a painter who took Fanny's friendliness as flirting and assaulted her. Convinced Carl killed his mother, Scott fatally shoots him. Ryan is disgusted, convinced that Natalia is to blame for assuring the boy Carl would be punished. Calleigh is more forgiving, and even takes apart the boy's insanity plea.
When Horatio and Delko learn Ray Jr. and several other boys were spirited away by a woman, Horatio realizes his nephew is being used by Riaz as a drug mule. Yelina shows him latex gloves with the tips cut off in Ray's backpack, indicating he's carrying heroin pellets. Delko hunts Riaz down and takes him on. Just as it looks like the CSI is going to lose the fight, Horatio shows up and finishes Riaz, at last avenging Marisol's death. Hoping to find Ray Jr. in Miami, Horatio and Delko return to their home base with Yelina. They soon find the woman, Anna, and one of the boys, dead in a warehouse. Anna tells them the boy started to get sick and she called a man to help. The man killed the boy and took the drugs he was carrying from his body.
Epithelials from the phone the man abandoned lead the CSIs to Angel Delmonte, a known associate of Miami drug lord Diago Matos. Matos denies knowledge of the boys' whereabouts, but Horatio knows he's lying. Ray Jr. calls Yelina to tell her he's carrying the drugs to save his father, but he hangs up before she can tell him his father is dead. The other boy traveling with Ray Jr. turns up in the hospital, ill from the drugs in his body, and he gives up the location of Ray Jr. and Matos's scheduled meet. Horatio interrupts a tense showdown between the two. He gets Ray Jr. to drop his gun, but Matos fires off a shot and Horatio fires at him, killing the drug lord. Horatio reluctantly bids farewell to Yelina and Ray Jr., but not before reminding Yelina they have family in Miami.
- David Caruso as Horatio Caine
- Emily Procter as Calleigh Duquesne
- Adam Rodríguez as Eric Delko
- Khandi Alexander as Alexx Woods
- Jonathan Togo as Ryan Wolfe
- Rex Linn as Frank Tripp
- Eva LaRue as Natalia Boa Vista
Guest Cast Edit
- Sofia Milos as Yelina Salas
- Christopher Stapleton as Raymond Caine
- Vincent Laresca as Antonio Riaz
- Brendan Fehr as Dan Cooper
- Carter Jenkins as Raymond Caine Jr
- It's revealed that Natalia is now an official CSI.
- With Horatio out of the country, Calleigh is temporarily promoted to the rank of Lt. and as such becomes the head of the Miami-Dade Crime Lab.
- Horatio eventually learns from Yelina that Ray Jr might be working for the drug lord now.
- Raymond is eventually discovered in a slum, bleeding and eventually dies from his wounds, his last words being to Horatio whom he urges to save his son, Ray Jr.
- Horatio and Delko eventually succeed in avenging Marisol's death by killing Antonio Riaz.
- Rex Linn (Frank Tripp) and Eva LaRue (Natalia Boa Vista) are promoted to series regulars and as such, are now part of the opening credits.