The Serbian army has fled through Albania to escape destruction at the hands of the Central Powers. In the course of its march through Albania a great many of the soldiers and their civilian followers have died from exposure, disease and attacks by Albanian raiders. Now the survivors have reached the coast, where Allied ships begin to bring them away to the Greek island of Corfu, recently occupied despite the protests of the Greek government.
If the Serbs hope for a respite from their calvary on Corfu they are cruelly mistaken. Disease continues to extract a heavy toll on their numbers. Allied preparations to receive the refugees have been somewhat lacklustre, meaning that there is a shortage of food and tents for them. Corfu is warmer than the Albanian mountains but an Ionian January is still cold and wet; without tents more Serbs perish in the rainy weather.
The small island of Vido is used as a quarantine for Serbs afflicted by infectious diseases. With only the most rudimentary treatments available they begin to die in large numbers. The island is too rocky to house the graves of all the victims. They end up being buried at sea, corpses tied to rocks to make them sink into their blue graveyard.
One night on Vido’s harvest of death (Wikipedia)