Don and his team investigate a murder at a horse track as Charlie digs deeper into the victim's life he discovers an elaborate gambling scheme and a connection to a third party, sending the case in a new direction.
An assailant opens fire in the FBI offices Charlie does not want to return.
Don takes stock of his life as he investigates the death of an ex-girlfriend under questionable circumstances.
During a school-shooting investigation, one of the suspects surprises Don and his team.
An Iraqi activist is killed on U.S. soil, and Don's team must unravel the woman's connection to Saddam Hussein as members search for her killer.
When a psychic, Kraft, leads authorities to a deadly crime scene, he offers to help Charlie, who resolves to prove that Kraft's abilities are no match for his mathematical findings.
Don and his team investigate a deadly anti-war bombing that bears the stamp of a 1970s activist who went missing 30 years earlier when accused of planting a bomb that killed two people.
An expensive piece of equipment is stolen from a college DNA lab, and the prime suspect is a student at the school.
The agents must stop an organ-trafficking ring when they discover that a young immigrant died while selling one of her kidneys.
Charlie searches for a link between robberies when the number of violent home invasions in an upscale neighborhood suddenly escalates.
When interference with a counter-terrorism exercise has deadly consequences, Don and his agents search for the culprit before more damage can be done.
When Don and his team find a strange code during a raid, Charlie suspects it is part of a plan to assassinate a Colombian exile living in Los Angeles.
Don asks Charlie to help narrow the list of suspects when an energy corporation CFO is found murdered on her doorstep just before she was to testify in a case of stock fraud.
Don and his team search for the stalker of a pop princess but, when a celebrity photographer is murdered, Don begins to suspect that the princess is not a victim.
Don and his team investigate a jewellery store heist in which the perpetrators kidnapped the owner's wife and daughter.
Don taps the expertise of Megan and Charlie when a federal judge's wife is murdered.
Don utilizes the skills he learned at the FBI to track two violent felons who have escaped from a prison bus.
Don enlists Charlie to help stop a series of copycat railroad accidents involving negligence and an undecipherable numerical code.
When a mathematician (Neil Patrick Harris) gets close to solving the Riemann hypothesis, a difficult math problem whose solution is worth millions, his daughter is kidnapped.
Charlie convinces Don to launch an investigation when an engineering student is found dead from an apparent suicide.