As Don investigates the prison bus crash, Charlie uses of probability analysis to conclude that the bus crash was not an accident, but part of a conspiracy to free a dangerous killer. Now, Don and Charlie must discover the killer's lethal agenda and stop him before he is able to carry it out.

When a UFO is spotted dangerously close to Los Angeles, Don recruits Charlie to help locate the mysterious aircraft's point of origin and is surprised when it turns into a murder investigation.

After an independent computer researcher with a contract with the Defense Department is found murdered, Don and his team are called in to find out who is responsible. After Don recruits Charlie to decode the murder victim's cryptic computer data, Charlie uncovers he was working on a secret and potentially damaging project, forcing Charlie to question the impact of his own life's work.

Don and his team are called when it is discovered that a truck driver and his big rig carrying radioactive material have been hijacked and are now missing. They are pressed for time to find the truck when the hijackers threaten to detonate a dirty bomb in an undisclosed location in Los Angeles if they don't receive $20 million in 12 hours.

Don and his team must stop a sniper who goes on a killing spree in Los Angeles.

When new information on an old case comes to light, Don thinks he may have sent the wrong person to jail.

After two teens are found murdered, the investigation leads Don and his team to uncover a dangerous counterfeit money ring.

While consulting with the National Transportation Safety Board at the scene of the wreck, Don learns that this tragedy is one of a series of recreated accidents involving railroad negligence. As is the pattern with the previous train wrecks, an undecipherable numerical code is left at the site, which Don recruits Charlie to solve. By breaking the code, Charlie is able to establish that this accident was a recreation of a deadly wreck that left only one survivor several years ago. Don's investigation leads him and his team to a dangerous standoff with their suspect, who has surprising ties to the railway system.

Don needs Charlie's help to find out why the daughter of a mathematician is kidnapped.

Charlie convinces Don to investigate a student's suicide in order to make sure that it was not murder.

Don relies on Charlie's mathematical insight to help stop a virus that has been killing innocent people in Los Angeles.

After a series of bank robberies, Don recruits Charlie to help chart the next robbery location, only to overlook the thieves' true motive.

While chasing a serial rapist, FBI Agent Don Eppes gets help from his brother Charlie, who is applied mathematics professor at California Institute of Science. Using his mathematical genius, Charlie attempting to calculate the "hot zone", an area, where the suspect is most likely to live.