There have been ups and downs in the history of Equestria, but not all of them are known to us. Princess Celestia herself, the goddess of the Sun, in attempt to protect her subjects from a terrible past, gave her enemies the key to the fall of her beautiful kingdom. Dark clouds are gathering, blotting out the sunlight, and the shadows of the past enveloping all her little ponies more and more . At the behest of fate, even if not by his own will, a human appears in this world. Now he needs to solve the mystery of the most famous legend in order to save Equestria.

This is a translation of Russian version of my fanfic:https://ficbook.net/readfic/6884436
Don't be too strict about grammar issues 'cause English is not my native language and I decided to translate this fanfic for practice