Deep inside the jungle of a forest beyond Equestria's borders, archeologists discover an ancient tomb of a tribe that is said to have been around for two thousand years and then suddenly they all seemed to either die off or vanish without a trace.
Open hearing about the tribe Celestia and Luna decide that their older brother would be the best candidate to go and figure out the mysteries that surround the old stone pyramid and find out weather or not finding this pyramid was a good idea or a trap.

Rated Teen for gore in the last chapter.
A bit of suggestive language near the end if you wanna call it that anyway.