Two parallel universes: one where our ancestors lived and Neanderthals went extinct and one where the Neanderthals lived and we died out. During a quantum computing experiment a Neanderthal physicist is accidentally shifted to our world. He becomes a celebrity here and back in his strange version of earth his partner is put on trial for his murder. This book is full of Well written characters and exciting scenes, the world building aspect of the Neanderthal society is very well done too. Awesome book, I was on the edge of my seat for the conclusion. Can't wait to read the sequel.