The God Emperor of Mankind is in Equestria, and he's looking for love. Good thing for him that Celestia is looking for the same thing. The problem is that he's a warmongering immortal monarch, and she's a benevolent alicorn princess, so clearly they'll get along swimmingly. Here's hoping Equestria survives their relationship!
Trying to spice up Celestia's love life, Luna signs her up on a dating website. Now Celestia has to go on a series of dates with other immortals. This should end nicely.
He's the God Emperor of Mankind, and she's Princess Celestia of Equestria. With these two dating, you can expect almost anything to happen. Hopefully Equestria survives their relationship in one piece...