A hot summer afternoon in the northeast. Residents of New York and Toronto look forward to the weekend. No one could predict what is about to happen.

In a matter of seconds, 50 million people simply fall off the grid. Phone lines and water systems fail, and thousands of people are trapped in elevators and subways. It is August 14th 2003, and the largest blackout in North American history causes 6 billion in damages. The official cause? Overgrown trees on power lines. But there’s more to this story than troublesome trees.

Just three days earlier on August 11th someone somewhere released one of the most damaging computer viruses ever written: Blaster. It was probably the biggest attack against the Internet ever.

Mikko Hypponen is one of the world’s most respected virus hunters. It is here at F-Secure, an anti-virus lab based in Helsinki, that he and his team first identify Blaster when it hits the Internet. What Astonished Mikko is the impact the virus has on the physical world. Blaster was the first worm that really showed that an attack like this can affect society and normal life.

Welcome to the world of viruses, trojans and worms in this Web Warriors documentary.