Horizon explores the murky and fast-paced world of hackers who are out to steal money and identities, and meets the scientists joining forces to help defeat them.

Exploring the murky and fast-paced world of the hackers out to steal money and identities and wreak havoc with people's online lives, and the scientists who are joining forces to help defeat them.

Horizon meets the two men who uncovered the world's first cyber weapon, the pioneers of what is called ultra paranoid computing, and the computer expert who worked out how to hack into cash machines.