The family wanted some potatoes for dinner, so one by one they all went down to the basement to get some... but none of them made it back alive!
The first to go down was Mikhail, the father. Oblivious of the gas chamber caused by the fetid potatoes that was awaiting him he trotted down the stairs only to lose consciousness and die on the spot. After a couple of minutes his wife Anastasia went to see what was taking him, and she too was overcome. Then their son Grigory went to investigate, and finally the granny went to check on everyone else, but never made it back either.
A little later when little Maria plucked up the courage herself to go and check, whereupon she beheld the ghastly scene. Luckily the cellar door was by now open, and the poisonous potato gas had dissipated. The only piece of good news in this otherwise tragic story.
It is true that potatoes can be highly toxic, and contain toxins called glycoalkaloids, which can be found in other related foods such as aubergines, tomatoes and peppers. The poison attacks the human central nervous system, with high concentrations causing headaches, diarrhea, weakness, and in extreme cases coma and even death!
Potato death is extremely uncommon, but perhaps the first Pilgrims to America were not that crazy to shun potatoes and tomatoes from their diet as being unfit for eating.