By the year 2186 humans have spread across the Solar System, colonizing the distant moons of Jupiter. Alyson Spenser is an astrophysicist, caught between her deep attachment to the beauty and magic of her work, and the voices—internal as well as external—that tell her to focus on what is practical, on the here and now. Alyson does her best to toe this party line, but she finds it a struggle. And then, something wondrous happens. She discovers a strange meteorite, and when she reaches down and touches it, she is instantaneously transported onto a spaceship in orbit high over Earth. The captain of the vessel is a streetwise smuggler from Jupiter named Anora Dane. Alyson finds her strange and frightening, yet she also glows with a vibrancy of spirit Alyson had nearly forgotten was possible. Faced with a reality she only ever half allowed herself to dream of, Alyson must choose where she belongs, following Anora to Ganymede, or returning to Earth.