The villagers of Kalachi in northern Kazakhstan are sporadically falling into a deep sleep - and no one knows why.
People suffering from the strange "sleeping sickness" fall unconscious almost instantly and cannot be woken for days. Many are unable to recall their time asleep, although some report terrifying nightmares.
Doctors and scientists flown in to the remote village - nicknamed Sleepy Hollow - are puzzled as to what may have caused more than 100 of the town's inhabitants to suddenly fall asleep.
The strange syndrome has been afflicting the village for a year and researchers are still no closer to an answer.
It was originally thought to be caused by Kalachi's close proximity to an old Russian uranium mine or leaking Radon gas, but tests have proven inconclusive.
Water, soil, blood, hair and even local vodka were tested for signs of a possible cause.
Saule Agymbayeva, the deputy head of the Esil District of Kazakhstan, said more than half of the town's 582 residents planned to relocate in an attempt to escape the mystery sickness, which has affected several citizens multiple times.
Some doctors suggest mass psychosis may be at the root of the phenomenon, but the case continues to baffle scientists.
It is even believed the villagers may have accidentally buried an elderly resident alive before the sickness was diagnosed.