In 1995 eight people were hospitalised after eating contaminated mussels in a restaurant. It took 10 years to identify a completely unknown algae species which caused the poisoning. In 2009 scientists embarked on an expedition, to study how fast this algae is spreading and it is not good news. This documentary reveals the global impact of killer algae and how the problem is becoming bigger year after year. We investigate the famous red tides, where tons of dead fish are washed ashore every year. This is a fascinating look at how scientists have developed an early warning system against the toxic algae blooms.