Gabriel and Riley must rescue a kidnapped member of CyberCom -- the man who invented the chip implanted in Gabriel's brain -- before secret technology falls into the wrong hands.
During an investigation into a suicide bombing at the U.S. Marine base, a discovery is made about a new, chemically undetectable bomb material; Gabriel is unable to finish a task.
Gabriel's chip is hacked, leading to him discovering that Mei Chen is still alive and that she possesses a chip even more powerful than his own.
Riley and Gabriel go on a covert mission in Syria in order to rescue American journalists being held hostage; the truth about Riley's past with her ex-boyfriend is revealed when they are forced to work together.
The daughter of a senator in Mexico is kidnapped by a cartel; Lillian uncovers a connection between her father (Peter Coyote) and the cartel.
Gabriel and the team go to Texas to help contain a deadly, quickly spreading virus and identify patient zero.
Gabriel and Cybercom investigate when artificial intelligence scientists are infected and killed by microscopic robots.
While in Bolivia with Riley to protect a presidential candidate from assassination, Gabriel is shocked to learn his best friend is the suspect.
When an aggressive virus wipes out Gabriel's memory, he thinks Jin Cong is good and helps him find a secret document.
When the FBI's witness protection database is compromised and witnesses are blackmailed, Gabriel, Lillian and Riley go to San Francisco.
As Riley and Gabriel track an infamous hacker, they learn the suspect may have been set up and a sinister group may be planning a nuclear attack.
Gabriel and Riley must determine who is responsible for framing Gabriel when he is suspected of murder; Tetazoo leads a manhunt for Riley and Gabriel.
Riley and Gabriel are shocked when the identities of sleeper agents embedded in the U.S. government are revealed.
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