An innocent looking schoolboy, who watches while his victims suffer and die, a cold war killing meticulously planned, and a kindly looking doctor who pays his patients the house calls from hell. All these killers used poison. It’s been called the coward's weapon because it’s stealthy, deadly and hard to detect.

Over the centuries, prisoners have been able to adapt their methods to the times, simply choosing a new and more deadly toxin to challenge and confuse.

But no matter how clever the killers thought they were being, science would eventually catch up. The days of the untraceable poison were numbered.