Witnesses relocated and given new identities by the US Marshalls are being found and killed. As the Marshalls seem to be unable to find out why this is happening or to stop the assassin Level 9 are activated. They are an ultra secret, cyber ops rapid response unit, designed to fight high tech crimes and to use top range technology to hunt down criminals. Their assignment is to find out who the assassin is and stop him.

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

From a tip supplied by a snitch Jack Wiley enlists the aid of Level 9 to raid a group of hackers who ar ein the process of selling a list of top secret NATO safehouses, in Iraq, to Saddam Hussain. The hackers wipe their computers and while Level 9 try to find the information they come across some stolen plane codes, used for controlling a new super-computer controlled plane. Later, while undergoing evaluation tests, the computer piloted passenger jet is electronically hijacked and crashed. It's only passengers, two supervising pilots, are killed. The hijacker soon makes his demands known and threatens to take down an airliner fully loaded with passengers if they are not met. Level 9 must capture this cyber-jacker and locate and de-program his digital bomb before it sends a plane full of passengers plummeting to their deaths.

Justin Malik ('Mail Call') is in a maximum security hospital prison, somewhere he has no intention of staying. Using an orderlies laptop he arrnages his own release and sets about getting in touch with, and meeting up with, the mythical main man of the hacking world, and number one target for Level 9, 'Crazy Horse'

A serial killer is targetting girls who work in the internet sex industry. He is tracing the home addresses of those who strip in front of their own web cameras and then killing them why they are online. Sosh takes this personally and begins her own 'cyber' investigation, against Annies instructions, and takes more and more risks while doing so. Meanwhile the rest of the team are running down leads in the real world, trying to catch the killer before he strikes again.

Skid, a hacker friend of Jargon, is shot by an international assassin but manages to escape and get to Jargon's place. Skid and some other hackers had managed to break into the Department of Defense restricted files and found details of a top secret chemical formula. They arranged, over the internet, to sell the formula to one of the worlds most infamous terrorists but at the last moment upped the price. What they didn't realise is that they now have not only the authorities, in the form of the FBI and Level 9, after them but also the assassin hired by the terrorist. Jargon realises that all the hackers are friends of his and is torn between his desire to help his friends and the fact that they are the sort of criminals that he is paid to track down.

FBI Deputy Director Holden kills himself and is then implicated in the theft of a number of top level, high security files. Annie was taught by him at Quantico and, even though it does not come under Level 9 mission statement, she gets the team to start investigating the circumstances behind his suicide. The team discover that Holden was running his own, unauthorised, investigation inth the murder/suicide of Annie's parents and that he could have been getting much closer to finding out the truth than someone wanted.

Hank Landry, a seemingly ordinary, law abiding man assassinates a United States Senator who was about to release a controversial, tell all book. Wiley thinks that there is some sort of conspiracy involved and wants a full investigation. Annie though is not convinced, especially when Wiley starts to compare the death of JFK. When the publisher of the book suddenly dies as well Wiley's theories start to become more plausible and he taps some of his contacts to find out how Landry was made to become an assassin.

Level 9 are at the site of a cyber gallery. The owner,Billl Baker, is showing off his new invention that creates digital images of famous masterpieces he owns. A group of 'crackers' called Black Echo have threatened Baker many times and are expected to try hacking into his opening and ruining his credibility. When they do attack though it is Baker's son, David, who turns out to be the target, not any of the paintings. Level 9 and the FBI start their investigations and search for Daivd and find that all the evidence seems to lead to 'Tibbs as the main suspect.

The first ever peace conference to be broadcast on the net is taking place at Fort Hope in America. Level 9 think that the opportunity for cyber terrorism will be too big to miss and that someone will hack into the live broadcast and send out their own messages/signals or cause some kind of crash. Their main suspect is a hacker called Moby J, who is known to have a grudge against the military, who are hosting the conference. To add to Level 9's problems they also have to deal with a General who dismisses them as a 'flavour of the month' and a female captain, who carries the codes for nuclear launches, who 'shot down' Tibbs when they both worked at the Whitehouse When contact is lost with a nuclear bunker everyone starts thinking that they may have more to deal with than just simple hacking mischief.

Annie finally gets what she really wants when Level 9 manage to catch the mysterious, and elusive, 'Crazyhorse'. Very soon though the question turns out to be whether they are the ones who have caugh ttheir nemesis or whether he is the one who has 'trapped' them, especially when Annie collapses with some unknown and seemingly undiagnosable illness. As the rest of Level 9 try to find out what she was poisoned with, and how it got into her system, Tibbs collapses with the same symptoms. Can the rest of the team find out what is going on before they to come down with this real virus or will 'Crazyhorse' end up the victor?

One of the two owners of the biggest computer company in America is killed by aletter bomb during the public announcement about their new program, a program that will bring about the end of ordinary mail. Level 9 are handed the job of finding out who killed him and why, an investigation that uncovers some unsavoury facts about the two partners and the formation of their company.

When a top hacker is killed in his hot tub Level 9 discover he was working for a top mob man, Alex Veedy. Sosh and Jargon discover that Veedy is setting up a meet with the legendary hacker, Cypher. Travis manages to intercept the email with the meet site and time and change it, making it possible to capture Cypher. Travis then replaces Cypher, pretending to be him so that he can infiltrate Veedy's organisation and find out what he needs a top hacker for.