CSI: Crime Scene Investigation is a fast-paced drama about a team of forensic investigators trained to solve crimes by examining the evidence. They are on the case 24/7, scouring the scene, collecting the irrefutable evidence, and finding the missing pieces that will solve the mystery.
CSI's work the case of a young actress who is killed during a horrible traffic collision. Initially, investigators believe the accident is just a drunk driver killing an innocent motorist until it is uncovered that the driver was the victim’s stalker leading the team to believe that the stalker deliberately targeted the victim. Following the evidence soon leads them to discover that the drunk driver was not at the wheel during the accident making the CSI’s take a new direction to find why someone would setup such an elaborate murder.
Sara returns and offers her help while waiting to get more grant money for her and Grissom's research. Greg, feeling like the low man on the totem pole, is upset when he is sent to what he perceives as a less than desirable homicide scene of a homeless man. Catherine soon gives Nick good news in the way of a promotion.
The CSI team investigates the murders of two unsavory characters, a porn producer and drug dealer, in a seemingly middle-class neighborhood. Initially, the evidence points to a troubled teenager in the neighborhood who happens to be the adopted son of a serial killer. Sara and Nick theorize that he may have taken his obsession with the occult to an extreme level and made them a reality. Langston soon discovers that the boy has a deformity that would make it impossible for him to have committed the murders. As they begin to take a second look at the evidence the team finds that a neighbor currently being touted as a hero is actually the killer. He was a hard-working father who became disgusted that the neighborhood he was raising his child in was becoming rundown with low-life pornographers and drug dealers and decided to take matters into his own hands.
A young man is found bludgeoned to death in the woods and the CSI team soon finds that the victim, a handsome but cocky tech-geek, was plotting to blow-up and rob the casino holdings safe where he worked . He enlisted the help of a shy but savvy co-worker, Paulie, who’s insecurities finally got the best of him when he killed the young man in a fit of rage. Paulie decides to go through with the robbery alone but Langston and Nick have already caught on to his plan and he ultimately suffers the same fate as his victim.
The racially charged story of a cop that kills another cop by accident and the infighting between the police and the local community that ensues as they work out the ugly details of the case. A veteran cop, who is advancing towards retirement shoots and kills a black man in a fast food joint. It appears as if the final shot was point blank, and after the man was already down on the ground. Catherine and Brass are called in to investigate. Catherine is the lead CSI in the case, and all the local police give her attitude for being defacto IA. She is unbiased until the facts reveal that the cop actually shot another off duty cop, and actually knew him. The CSIs figure out that the final shot or "Coup de Grace" came from another gun. It seems as if the veteran cop is cleared of murder, but asked to take a leave of absence. Langston sees the cop as he gets into his car at the end of the episode and blows his brains out. The shame was too much for him. In his autopsy they discover that he was actually legally blind, but too proud to tell anyone. It was an accident after all.
A well known college football coach is murdered, and our CSIs are brought in to investigate. They discover that one of the football players on the team has a terrible crime in his past and this crime set the stage for the coach’s murder. When the very popular local college football coach is found bludgeoned to death in his house, the CSI's have to look at the evidence, and the people who were closest to him. He lead a team filled with loyal players. Some were like sons to him. One of the players had a bit of a past, and the CSI's discover that he was in a car accident some years back, and a young woman was in the car with him when it went under water. She was killed, and the only person that the player told was the coach. He held this secret for years, but recently the player suspected that the coach was going to talk, so he murdered him.
The CSI's track a horrifying crime in a twisted tale of revenge. What seems like a random beating in an alleyway, and a near by robbery/murder at an electronics store, is actually two crimes linked together. The murder is precipitated by the hidden rape of a man. The brother of a young woman committed the rape and beating to punish the man for dating his sister. Nick is particularly kind to the man, and helps solve the crime.
The third part of the CSI crossover:
Langston is still on the search for Madeline Briggs. A local weather girl, Deedee, is found dead outside of the Tangiers Hotel & Casino, dressed as a hooker. When the team processes her, they find blood from Madeline on the earring Deedee was wearing along with a relatively recent tattoo. They posit that Deedee and Madeline were probably living in the same place and had the same pimp. The team goes to a nightclub and spots a hooker, Diane, with that same tattoo as Deedee. They bring her in on a bogus charge only to get a lead when the hooker calls her pimp from the station. They follow Diane to a house where they see one of the pimps, Anthony Samuels, wearing the other earring seen on Madeline Briggs. Searching the house, Langston finds a bloody mattress as well as a lock box filled with money, casino chips and driver’s licenses, including Deedee’s. They find Diane, beaten, in the house and she divulges that she had another tattoo that was covered over by Anthony, leading the team to believe that she used to belong to another pimp – a Russian, Dmitri Sadesky, who’s actually a professor at WLVU. Langston processes the mattress and finds positive matches to the blood of both Madeline Briggs and her fetus. Meanwhile, Catherine goes through the security footage from the Tangiers to try and figure out what happened to Deedee and discovers that Diane was the one who actually killed her; jealous of the fact that Anthony liked Deedee more than her. Dmitri is caught with evidence in his car from the leg that was found in Miami by Horatio and Langston and they discover more dead women’s bodies buried in the desert. Caught, Dmitri helps them bring down the human trafficking ring and admits he had Madeline but then let her go after seeing Madeline was no use to him. Langston finds a way to send her a text message to tell her that her mother loves her no matter what has happened. This message reaches Madeline who picks up the phone to call her mother.
A severed head is found in the middle of a bowling tournament and the CSI team is called in to find the missing body. The murder is tracked to the jealous girlfriend of the victim and his biggest bowling opponent. The episode opens with a bowling championship, where the top two bowlers in the league are battling it out. As one of the champions gets up to have his turn, he reaches down to pick up his ball and a severed head of a man comes rolling up. The CSI's are initially led to believes that his opponent is the murderer, but soon find out that his girlfriends, who seemed quite innocent the whole time, was the one who cut his head off after he was killed by his opponent. She put it in the bowling ball return to seek revenge on the man who murdered her boyfriend.
Nick, Greg and Hodges kidnap Henry for his birthday and take him to an off-the-strip biker bar. On the way to the bar their car gets sideswiped and flips over. All of them are miraculously fine, except for Henry's sprained ankle, and they make their way by foot to the bar only to find it has been closed down due to a Hepatitis outbreak. Instead of a goodtime they find a double homicide and a couple of odd characters that may be murderers. A young woman is found murdered while her sickly sugar daddy is fast asleep. When he suddenly dies during interrogation, they find he has been implanted with a second appendix - Dr. Jekyll strikes again.
In a twisted tale of attempted suicide, the CSIs dig to find the truth about a young woman, found dead, wrapped in a quilt on the side of the road. A shootout in a gun store leaves a chaotic mess which later ties into the death of the young woman. The team searches the victim's apartment and finds that she is having a romantic relationship with "the man in the red shirt." They cannot track down the whereabouts of this mysterious man but fear he is the person who killed the victim. What they do discover in her apartment is her dead dog; he had been poisoned. "The man in the red shirt" turns out to have been the victim's boyfriend, both suffering from bi-polar disorder, and had a secret suicide pact. In a twisted act of love, he poisoned himself at her apartment and left the poison for her, but her dog ended up ingesting the poison before she arrived home. When she found them both lifeless in the apartment, she assumed they were dead. Her boyfriend was really only unconscious, and when he awoke, he found her dead from a self-inflicted gunshot wound.
Two beautiful women are murdered in a Las Vegas hotel by an unexpected killer, an accountant. He was the victim of a scam and murder was his revenge. The investigation starts with the dead body of a beautiful blonde in a hotel hallway. Everyone on the floor is questioned, but the leads go nowhere. Little by little the CSIs uncover the fact that she was working with another girl as con artitsts. They would seduce unsuspecting men in the hotels on the strip, then take their ATM cards and clean out their bank accounts. But this con went sideways, and the guy they tried to rip off got his revenge. He killed one of the girls in her hotel room, and the second girl tried to cover it up and go after him for one last con. When she boldly went back to his hotel room, he overpowered her. In the mean time, Langston continues to track Dr Jekyll. A case presents itself that feels like it might be Dr Jekyll's work only to find out that it was just a hack doctor helping poor people who cannot get medical attention.
During a high profile golf tournament, a golf pro is found dead and the CSIs discover strange connections to this victim including a stepson, himself a golf pro, who has been competing with the victim for some time, and an estranged ex-wife who may have had motivation to kill him. In the end, The CSI team discovers that it wasn’t murder but an unfortunate accident. The victim and his step son were fighting on the greens and in a moment of anger, the victim flung his club into the ground causing it to break off, striking himself in the head. His stepson was watching the whole horrifying event and ran from the scene without telling the police.
In a tale of teen drag racing a la James Dean and the 1950s, our CSIs get caught up in the mystery of what happened to a young man who drops dead at school with a severe brain adema and his girlfriend who has gone missing. The details of the case lead the CSIs to the underbelly of street racing, and souped up drag racing cars. They investigate the father of the young girl's best friend, who is also an auto shop teacher at school. The trail leads back to him and his daughter in a tangeld web of deadly competition.
A band member of Rascal Flatts is electrocuted by a guitar and forgets he's a country singer. A guitar tech plans the electrocution so that he can have his shot on stage. The A story is dealing with a CIA agent threat floats up on shore of Lake Mead. What looks like a murder and poisoning, turns out to be a suicide. The CIA agent had written secret memo turning over secrets from the cold war and the toppling of East Germany. When his very liberal son got a copy of the memo, he threatened to disseminate it to the world. He hated his father for being absentee and a member of a covert government agency. At the end of the episode, the Rascal Flatts band member recalls who he is and rejoins the band for an onscreen performance.
When a boy is found murdered, the CSI team soon find the victim is tied to an old case where a man was convicted of killing his wife. There was blood evidence found under the fingernails of the boy at the crime scene. This evidence leads the CSIs to a high powered lawyer who is working to free the man that was convicted of killing his wife. The team finds that the young victim had two best friends who were trying to earn some money by breaking into the evidence locker at CSI in order to tamper with evidence on the old case. The boy who was trying to help his two friends, but ends up falling from a shelf high in the evidence storage unit. An old CSI who now works the storage unit covers up the death and plants the boy's body in a parking lot so that he will not be blamed for letting this boy slip into the storage unit -- even though it was an accidental fall.
Catherine and Vartan stake out a drug ring in an upscale hotel while the rest of the team investigates a murder linked to “panty sniffing”. Catherine and detective Vartan are thrown together in a hotel room for 24 hours while they monitor and stake out an ecstacy lab in the room next door. This brings them closer together, and Vartan admits to Catherine that he is not looking for something casual. In the mean time, Nick and Greg are on the strange case of a fetish that has become a big business -- panty sniffing. The murder of a hotel employee, who was also a lingerie model on the side, leads the team to her murderer - the hotel security guard, who was also her boyfriend.
Langston and the team investigate the brutal murder of a family, eventually tracing the killer to the house next door where they discover a machine shop where specialized medical tools are being constructed leading them to believe that they may have stumbled upon the home of Dr. Jekyll. They soon trace the missing homeowner to his mother’s house, where he is found crazed and raving, having killed his mother. The man dies suddenly, however, when Langston and Robbins examine him, they discover a small radioactive pellet embedded in the man’s brain. They surmise that this pellet is what caused his killing spree and death and realize that the dead man was actually helping Dr. Jekyll create his specialized surgical instruments. Dr. Jekyll killed him as well, effectively eliminating the one person who could identify him.
When a group of three high school CSI Explorer Scouts are given over to Wendy and Hodges in the lab for training, they go over an open but cold case involving a woman who is found dead in a burned out building, but without a burn on her body. However, as they walk through the teaching case they begin to discover clues that may lead to an unexpected case resolution. Story will be told in flashbacks/fantasy segments in which the audience will see how Hodges and Wendy see themselves. Instead of seeing Langston or Catherine in the flashbacks we see Hodges and Wendy acting like Langston and Catherine, solving the crimes as CSIs.
When Lindsay, Katherine's daughter, is playing the lead in her high school's version of Cabaret, a gruesome murder is discovered on campus. A young man who was not well liked at the school turns up dead in the storm drain. He was a racist and a part of a white supremacy group of boys who commited hate crimes. There are multiple murder suspects and then the story takes a sharp turn as we learn that he had actually befriended the African janitor at the school. He became interested in the janitor's history as a refugee from war torn Rwanda. The man relayed his terrible stories of genocide and losing his entire family to the horrors of the war which hit a cord with the young boy. But when the boy found out the man was lying, and that he actually was one of the mass murderers who had moved to the U.S. and changed his identity, the boy went after him. The janitor killed the young man to keep him from exposing his secret.
In an old style Vegas episode, we meet a modern day version of the Sunshine Boys. Tim Conway guest stars as a legendary old comic from the hay-day of Vegas, who is reuniting with his partner to play a big Vegas casino. When his partner seems to be forgetting the material, and is very much off his game, the old comedy duo faces some challenges. The legendary comic has married an ex-showgirl who has quite a colorful past. When his partner ends up dead, she is a suspect, along with many others. At first it looks like a death by natural causes, but our CSIs find out that he actually was drowned by ice. Someone drugged him, and then shoved loads of ice down his throat, creating the perfect murder. Without the diligent work of Doc Robbins and David in the morgue, this murder would have been passed off as an accident. In the end, the legendary comedian killed his old partner to save him the even worse death of "dying on stage".
A mother thought to be grieving for the loss of her family three years ago becomes a suspect in a CSI investigation.
The CSI team must investigate one of their own when Langston is accused by a former colleague of being part of the Dr. Jekyll murders.
The CSI's lives are on the line as they close in on the elusive Dr. Jekyll, and more than one member of the team may not live to see his capture.