It is the 22nd century. Interstellar travel is possible, but colossally expensive, so humankind's efforts are focused on the only nearby Earth-like world. Isis is rich with plant and animal life, but every molecule of it is spectacularly toxic to humans. The whole planet is a permanent Hot Zone.

Zoe Fisher was born to explore Isis. Literally. She has been cloned and genetically engineered to face its terrors. But there are secrets implanted within her that not even she suspects - and the planet itself contains revelations that will change our understanding of life in the universe.