An ex-boyfriend throws acid into a young woman's face, then uses a series of disguises in an attempt to throw police off the scent. But number plate recognition cameras help prove he was in the area and responsible for the horrifying attack.Meanwhile, a new online system is set up in Cumbria, enabling witnesses and victims of crime to upload video evidence and send it direct to the police. And a stolen Land Rover is recovered and returned to its owner in less than 24 hours, thanks to a hidden tracking device.