With the help of her friends in Ponyville, the Tantabus was subdued...but what about Celestia? What about Luna's closest friend, a pony who had no idea what was going on in her little sister's mind?
Twilight couldn't remember ever having seen Princess Celestia get sick. That simply doesn't happen to alicorns. And yet there she lies, on her bed, delirious. If only she knew how to help.