Just recently played A Hat in Time. We're never told, but every detail points at this being the fantasy adventures of a little girl with A LOT in common with Calvin from Calvin and Hobbes, an overabundance of imagination and hyperactivity. Charming and funny (well, save for Queen Vanessa, which I feel was instead a masterpiece in ambience). Loved it, gotta try the DLC. Just be ready for hard platforming at many places.