In the future, instead of terraforming planets to sustain human life, explorers of the galaxy transform themselves. At the turn of the twenty-second century, scientists make a breakthrough in human spaceflight. Through a revolutionary method known as somaforming, astronauts can survive in hostile environments off Earth using synthetic biological supplementations. With the fragile body no longer a limiting factor, human beings are at last able to explore exoplanets long suspected to harbour life. Ariadne is one such explorer. On a mission to ecologically survey four habitable worlds fifteen light-years from Earth, she and her fellow crewmates sleep while in transit, and wake each time with different features. But as they shift through both form and time, life back on Earth has also changed. Faced with the possibility of returning to a planet that has forgotten those who have left, Ariadne begins to chronicle the wonders and dangers of her journey, in the hope that someone back home is still listening.