A woman's body is discovered in a small press box at a high-school football field, apparently the victim of strangulation. The evidence leads investigators to two convicts, one of whom is still in prison. At the crime lab, an explosion destroys key evidence and leaves Greg and Sara injured.

Two couples meet in a bar and one of the couples is murdered. When a second couple is murdered in a similar fashion the team suspects a pair of serial killers are on the loose. The case is complicated by leaks to the press and a judge reluctant to issue a warrant. Catherine gets some troubling news about her father's murder trial.

When the lead suspects in Grissom's serial killer case are murdered, Grissom suspects an inside job. Grissom and Brass are at odds when Grissom suggests it was a cop. Catherine and Sara investigate what happened to a college football fan when his bloated body is found in a bathtub.

Grissom and Warrick get the case of an old woman found mummified in her closet. Sarah and Nick arrive to investigate a breaking and entering to find a raped teen. These cases are not as disparate as they first seem. Catherine looks into a gun found by a boy. The gun is connected to a week old murder across town that Warrick caught.