Thorax is not the first Changeling to reform his hive... but all hives who have done so in the past have been cursed to extinction. Celestia assigns Daring Do to find out why, and stop history from repeating before it's too late.
On the Winter Solstice, Starlight and Twilight's definitely-not-a-date is interrupted by Sunset Shimmer arriving from the future. Warning of a disaster, and claiming to be Twilight's future wife.
Sunset and Twilight are dating. They know Rarity has feelings for Sunset. They've asked her out to dinner together. Rarity is not panicking. It's far worse than that.
Twilight has loved playing General since she was a filly. Tempest wants to protect Equestria from someone else like her. Together, the two have such good intentions...