Jacob and Princess Luna share a similar interest in cultural heritage and history. Together they like to explore ancient ruins that predate the ponies' arrival to Equestria. Until one of them contained something they could never have expected.
When Discord revealed the Blue Flu to be a big fib, everypony thought that that was water under the bridge. Little did they know that he needed the tea for another reason. To turn Princess Celestia's life upside down.