Twilight had been invited to spend the holidays together with her brother and Cadence in the Crystal Empire. She gladly agreed, and was happy to be there along with Sunburst and Flurry, even if she missed her other friends a bit.
But that wasn't too much of a problem. Plus, she'd finally get to see Tempest again. Only, Cadence hadn't mentioned that part until hours before Hearth's Warming Eve. But that was fine. She just needed to find a present in time.
And possibly keep it a secret. And possibly keep it in the first place.