Tunguska
The Tunguska event was an explosion, probably a meteor. Why is there a suggestion that there is something mysterious about the "Tunguska event"? The premise of the show makes no sense.
share1) The show is fiction. In fiction, things don't have to be based in reality. That's why it's called fiction.
2) You yourself used the word "probably" in describing the explosion. That means there is uncertainty about the cause of the event. Uncertainty is what creates mysteries. Mysteries make for good stories.
3) The premise of the show is very easy to understand, provided you possess the intelligence to understand how fiction works.