What begins as a straightforward holiday weekend for Sir Edward Leithen in a splendid stately home in the Cotswolds soon turns into something altogether different when one of Lady Flambard's other guests, the enigmatic Professor Moe, enlists the help of Leithen and his companions in a bizarre experiment to glimpse the future. For those who take part, the consequences are dramatic and Leithen's formidable powers of reasoning are brought to the fore.