Don and Megan are called to the murder scene when the CFO of a powerful energy company - who was about to testify against her fellow executives - is murdered at her home and her son is the only witness. Knowing there could be thousands of disgruntled ex-employees, Don asks Charlie to narrow the list.
The FBI becomes involved in the stalking of a popular singer after she is threatened by an intruder in her house and reveals a series of threatening letters she\'s received through the mail. Charlie determines the letters are from two different people after analyzing the handwriting. When a photographer is found dead near the singer\'s house, Don believes the photographer was murdered and his death is somehow related to the stalking case.
Don and his team are called in when a woman attempting to rob a jewelry store in Beverly Hills is shot by a security guard. Charlie assists the FBI by using the keyless remote from the woman\'s car to help identify her and locate the store owner\'s kidnapped wife and daughter.
Don and Charlie investigate the murder of a judge\'s wife who was shot in her garage. It\'s unclear whether she was the intended target or her husband, who was hearing a death penalty case involving a gang leader. As the investigation continues, Don reconnects with a prosecutor whose life may also be in danger.
A dangerous felon escapes when a prison bus crashes and the FBI has reason to fear he\'s intent on revenge against the witness whose testimony put him in jail. However, finding the elusive killer proves to be a complicated challenge. Don teams up with Agent Billy Cooper, his former partner from the FBI\'s Fugitive Recovery Division, and Alan worries that Don\'s going to return to a more dark and obsessive time in his career.
Don and Agent Weston of the NTSB investigate eyewitness accounts of a mysterious unidentified object flying dangerously close to downtown Los Angeles that has raised concern of a terrorist attack. After Charlie is recruited to help with the investigation, it is discovered that the flying object is part of a new technology that could revolutionize air travel. But the investigation takes a turn when they learn that the lead engineer is found murdered.
A senior computer-science researcher working on a classified government project is found murdered in his Hollywood Hills home and data has been stolen from his computer. The investigation reveals the victim was going through a bitter divorce and was trying to keep his wife from getting his money. Charlie also learns the project on which the man was working might have involved baseball.
A truck carrying radioactive material is stolen, and the thieves threaten to set off a dirty bomb in L.A. in 12 hours if they aren\'t paid $20 million. While Don attempts to track down the truck, Charlie tries to come up with the most likely location where the bomb may be detonated to inflict the most damage to the population.
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.
A man wanted for stock fraud is found garroted in his apartment, and the crime is eerily similar to a murder committed a year earlier, a case in which Don closed when an ex-con confessed. Now, Don must re-investigate the old case to determine if he put an innocent man in jail. He asks Charlie to go over the evidence to see if he missed anything the first time around.