In part one of this two-part seventh season opener Grissom and Catherine handle the case of a women's dead body found at Cirque du Soleil by a performer. Meanwhile, an investor at one of Sam Braun's new casinos is shot to death during a party on the rooftop. Catherine's life is in jeopardy after visiting a nightclub with Nick. Grissom finds a miniature replica of a crime scene that he is investigating.

In the second part of this two-parter Grissom investigates the murder of an aging rockstar who is found dead in his kitchen with an exact replica of the crime scene on the counter next to him. Meanwhile, Catherine probes her own abduction and learns that someone may be targeting her family.

Coming straight from the perspectives of five people: Donna, Rebecca, Jack, Lou and Ray. All with one thing in common. They’re all dead. Brass and Catherine get to handle the case of Donna, who’s a cop from San Francisco, moonlighting as a bodyguard. Warrick and Greg work the case of Rebecca, who’s a former supermodel who died while hiking with her new husband Gavin. Nick and Sofia handle the case of Jack, a returning veteran from Iraq, who was killed in front of his wife and baby daughter who he just met for the first time. Grissom and Sara take the case of Lou and Ray whose bodies were found in Lou’s garage.

Innerhalb kürzester Zeit wird ein Mann zu Tode geprügelt und es gibt noch zwei weitere Opfer, die überlebten. Der letztere jedoch nur Dank Gregs Eingreifen.

Die beste Freundin und Geliebte eines Priesters wird in seiner Kirche gekreuzigt. Es gibt viele Verdächtige, darunter eine Schwester und der beste Freund des Opfers und des Priesters.

Grissom attempts to get a confession from a neighborhood pedophile by having him help in locating two missing boys. The sex offender is the main suspect. The investigation is more complex than the team ever thought it would be.

Eine alte Frau wird ermordet. Zunächst tauchen als Motive unter anderem ihre starken Schmerzmittel auf, doch dann bekommt Grissom ein exaktes Modell des Tatorts zugestellt. Der Modellmörder hat wieder zugeschlagen.

Zwei eineiige Zwillinge sterben in derselben Nacht, doch offenbar wussten sie nichts voneinander. Grissom und Catherine wetten darum, ob die beiden Fälle miteinander zu tun haben.

Im Lake Mead wird der Cadillac und scheinbar die Leiche eines vor 30 Jahren verschwundenen Mafiosos gefunden. Sein Geist scheint seine ehemaligen Angestellten zu ermorden, weil sie ihn damals ausgeraubt und angeschossen hatten.

Grissom investigates when a worker at a poultry processing plant is found dead in a stun bath used to electrocute chickens before they are slaughtered. Nearby, a miniature replica of the crime scene is discovered. It's eerily similar to two other replicas left at scenes of homicides. Also, a man and a dead woman are found stuck in cement at a construction site; and an elderly Russian woman is discovered dead in her apartment with her head in a gas stove, but Warrick thinks she was murdered.

Trotz Catherines Aussage wird ein mutmaßlicher Mörder freigesprochen. Da sie von seiner Schuld überzeugt ist, überführt sie ihn mit Nicks Hilfe eines anderen Mordes.

The team has a hard time trying to understand Michael who has become a team member since Grissom’s teaching hiatus. They investigate the murder of an unidentified girl who may have been killed by a serial killer who has been killing since the early 1970’s.

Ein Politiker, der durch den Kampf gegen Drogen bekannt wurde, wird in der Wüste ermordet. Um den unauffindbaren Verdächtigen aufzuspüren, fingiert das Team einen Tatort und lässt die Presse glauben, der Mörder sei verhaftet.

Nick and Keppler investigate the bizarre world of the black market sales of body parts after they find a body that has been burned and the organs removed. The rest of the CSI team investigates the death of rich woman who was killed in her own home.

Grissom returns from his sabbatical; Keppler is put into a compromising position when the bodies of a Trenton police officer and a hooker are found in a hotel room. The man who found them is a retired New Jersey cop and close friend to Keppler, who doesn't reveal their relationship.

Grissom erhält ein Paket, in dem ein weiteres Modell ist. Obwohl der Mord noch nicht geschehen ist, kann er ihn nicht verhindern.

Grissom and his team are discouraged when they find a pool of blood as they begin investigating the disappearance of a high school basketball star and his cheerleader girlfriend.Grissom's quip that the young lovers may have run off to Mexico is soon quashed by the discovery of drops of blood by Ryan's vacant parking spot at the school. After finding a letterman jacket and cheerleading sweater in the field house and a pool of Ryan's blood nearby, the team tries to determine what went awry.

Sara hält die Hand eines Mädchens, das stirbt. Seine rätselhaften Worte verfolgen sie, während sie das Haus untersucht, in dem mehrere Revuegirls getötet wurden.

Zwei scheinbar zusammenhangslose Fälle werden zu Einem. Das tote Mädchen wurde von der Limousine des zweiten Tatortes zu Tode geschleift.

Während das reguläre Team Fälle bearbeitet, versuchen die Labormitarbeiter unter Leitung von David Hodges eine Verbindung zwischen den Modellen herzustellen: Chlorbleiche.

Several suspects in a murder case are UFO-club members who believe shape-shifting aliens have been working to conquer the human race for centuries

Grissom investigates when a sadistic client tries to murder Lady Heather (Melinda Clarke), who makes the probe more difficult when she refuses to name her attacker. Also, Grissom's reunion with Lady Heather makes Sara uneasy.

As the CSI's continue their search for and discover the identity of the "Miniature Killer", Grissom and Sara's relationship gets exposed to the rest of the team as she goes missing during the investigation. The "Miniature Killer" is finally captured, but not before a member of CSI becomes the killer's final victim.