Applejack and Rainbow Dash are expecting Braeburn and his mystery marefriend to join them for a double-date, but neither of them would have expected just who that marefriend was.
A chance meeting at the bar blossoms into a fiery love/hate relationship between Lightning Dust and the only pony in Equestria brave enough to handle her.
Lightning ends up drunk in Appleousa and becomes Braeburn's bodyguard. Somewhere along the line, she got pregnant and now they'll have to deal with that.