For two years the villagers of Kalachi in Kazakhstan have been suffering from an inexplicable disorder, where they fall asleep for no apparent reason. The indiscriminate illness has no cure.

Episodes begin without warning, and those affected never know if they will wake up again. Its causes and consequences remain unknown despite multiple attempts by medics and scientists to solve the riddle.

Now the RTD team goes to Sleepy Hollow, as it has come to be known, to undertake its own investigation.

Related: The second visit of RT Doc to the village of Kalachi affected by the mysterious sleeping illness