The city is in a panic as a sniper goes on a shooting spree and randomly kills several people, including a postal worker. The investigation reveals that more than one shooter is at work. As Charlie works the case, he's frustrated by a sniper expert Don brings in to help out.

After four people nearly die from poisoning, Don learns someone is tampering with nonprescription drugs. When the perpetrator publishes a manifesto in a local paper, Don is led to believe the person may be a former employee of the drug company that manufactured the drug.

Don has a problem. Crystal Hoyle and her boyfriend Buck are going on a robbery and killing spree. Their terror is spread over seven states, and Charlie is called in to help. However, problems between Alan and Charlie may hinder Charlie's concentration.

David tries to get information from one of Crystal's old boyfriends, but he isn't helping. Things get personal for the team when Crystal kidnaps one of them.

When a jet crashes in the middle of a forest, Charlie suspects that there is more to the crash than what meets the eye.

Two rock climbers in possession of a large stolen diamond are killed, and Don and the team hunt for the murderers; Charlie considers whether he should have his FBI clearance reinstated.

When Amita is abducted, Don and the team’s frantic search for her leads them to the delusional head of a cult, but it is up to a distraught Charlie to discover what the suspect’s bizarre plans for her are.

While tracking down a felon running a heroin ring inside a prison, Agent Ian Edgerton becomes a murder suspect when the informant he meets with ends up dead, sending a desperate Edgerton over the edge when he takes a member of Don's team hostage.

After Charlie and Amita get married and begin preparations for their London adventure, they put a slight hold on their wedded bliss when they assist the team in helping Don track down the whereabouts of his gun after it goes missing.