Level 9, a clandestine, government-backed rapid-response strike force aimed at fighting high-tech and computer crimes, battles the violent machinations of a crazed hacker — who uncovers the identities of people in the Witness Protection Program and kills them for profit — and also finds that the hacker is part of a much larger scheme.

Level 9 is given the job of stopping a hacker called Thrillseeker from destroying a communication satellite system whose loss would severely compromise America's security. Annie sends Travis undercover at a hacker convention called DefCon, in Las Vegas, to see if he can find out who Thrillseeker is.

L9 lets a hacker escape from prison, in the hope that he will lead the government to the elusive master hacker CrayZhorse. But the hacker has other plans — and his first item of business is to kill Annie.

Jargon is torn between duty and friendship when some of his hacker friends run afoul of both the government and a terrorist network. As much as Jargon wants to help them, his job is to bring them to justice — no matter the cost.

A cyber-hijacker who has the power to remotely seize control over passenger aircraft threatens to crash a fully loaded commercial airliner if his demands are not met.

Annie investigates the suicide of her FBI mentor and discovers that he had conducted an unauthorized investigation that found new evidence regarding the murder-suicide of her parents. As she digs deeper, the shocking truth of what happened all those years ago places Annie in danger — because someone doesn't want the truth revealed and will stop at nothing to bury it forever.

An international "cyber-summit" for peace is disrupted when a series of betrayals results in one of its participants acquiring an armed nuclear warhead. With time running out, Level 9 must infiltrate the summit, neutralize the terrorists, and disarm the bomb before it vaporizes Washington, D.C.

Following the murder of a virtual sex show performer, Sosh leads the hunt for a serial killer who finds his victims online.

A top-secret CIA brainwashing operation uses e-mails to trigger assassins — and when Level 9 gets too close, one of its own is turned against it.

An elaborate abduction scheme is made even more disturbing when the kidnappers use digitally altered video and photos to frame Tibbs for the crime. With his own comrades from Level 9 hunting him, Tibbs must use all his wiles to find the real kidnappers and prove his innocence before time runs out for the victim.

The capture of a mysterious bearded man leads Annie to believe they've caught CrayZhorse. Then a series of mysterious poisonings threatens to wipe out Level 9 unless an antidote can be found — but acquiring the cure for the toxin reveals a traitor in their midst.

A deadly letter-bomb attack leads the L9 team to uncover a tangled web of family secrets and cruel betrayals, which cast a sinister shadow on the history of a company that is promising to help create a "paperless world."

Travis impersonates a hacker to capture a gangster who has been covering up his online scams by murdering his hacker accomplices. But the undercover mission takes a perilous turn when Travis falls in love with the mobster's sister.