An alliance of humans and alien species form a mission to investigate a Dyson Sphere, codenamed Cuckoo. Storyline involves the investigative team's moral/ethical problems involving Tachyonic Replication, the method of travel used to reach Cuckoo. (From the book cover, "Tachyonic replication was a marvelous invention. A man could send copies of himself anywhere. If one got killed, so what? He could always send replacements!") Additionally, the story involves the struggles of a young Cuckoo inhabitant named, "Fifteenth", against the cannabalistic masters of Cuckoo. All in all, it's an interesting read with fine concepts and characters.