The ability to see other-dimensional rings that float in Earth's atmosphere was a late mutation of a few space-age humans. Daryl was under the care of the institution for muters, and she had discovered that if you jumped through the right ring at the right time it would land you in another dimensional world and another shape.
Spaceling is the story of Daryl's desperate efforts to unravel the mystery of why she was being held captive and of what was really going on in a certain alien dimension. Because she was sure it was all bad and that someday everyone would thank her for the revelation.
But instead everyone was engaged in a wild effort to hold her down, to keep her on this Earth, and to keep the world simply intact!