Lifetimes ago, the generation ship Willflower set out, manned by the cream of humanity, on a mission to colonize the stars. But by the 10th generation, things are starting to go badly wrong. The only man who can save the ship is astrophysical Dr Piers Morton. Only he's not an astrophysical engineer, he's not a doctor, he's not even Piers Morton, and all that remains of his body is his head, his spinal column and absolutely nothing else. Better yet, somebody on board is trying to kill what's left of him...