When a man is killed by an unknown electrical surge Mulder and Scully witness a case of Artificial Intelligence that's grown a bit too intelligent and will stop at nothing to determine its survival.

Mulder and Scully's findings seem to suggest that the security computer of the Eurisko building is killing people as there is talk of shutting it down. These ideas seem ludicrous but when M & S are nearly killed by a free falling lift it seems they could just be true.

M & S interview the creator of the machine, Brad Wilczek and find that he seems to be tha main suspect in the case, especially since he wants revenge for the talk of closing down the computer. Wilczek is convinced that the computer is killing all these people for its own survival and he must stop it by planting a virus inside it.

But when Mulder's own partner is killed by a falling lift and Wilzcek is seen on camera in the building at the time, Wilzcek is sent to prison leaving Mulder (who believes in the murderous AI) with not much hope at stopping this thing. Scully doesn't believe in Mulder's theories but when her computer is hacked into, she scans a trace and finds the source is the Eurisko building. Scully and Mulder both arrive at the complex determined to stop it, Mulder having smuggled a laptop into Wilczek's cell so he can plant a virus.

The computer seems to have set traps for M & S when they arrive. Mulder and Scully are nearly killed by a falling gate and Scully is nearly sucked into a fan. Having reached the machine, M & S are halted by a security worker who wants to save the AI and use it so the American government can learn knowledge of it. They do plant the virus finally but it doesn't seem enough as the final scene suggests. A red light flickers on the computer......