This game strongly reminds me of Owlor's pony-based games, even though the game never says that the protagonists are ponies (or humans, for that matter).
Your sister has sent a curse at you, and you have to cancel it out somehow. This is a navigation-based Twine game, and you have an inventory of sorts (you can pick different birds to follow you, and so on).
This game was pretty enjoyable; I would give it 4 stars, but it has some glaring errors, like Twine 'if' errors that post big messages on pages that occur in every playthrough. If those were fixed up, I'd bump up the score.