When Dr Nathan Frost, a lecturer in German literature at Oxford University, is invited to a lavish party at the country house of a wealthy businessman, he knows there'll be a price to pay. After all, as an expert on the legend of Faust and Mephistopheles, he can recognise a deal with the devil easily enough. But even he's not expecting such a sinister end to the evening.

Called to investigate a suspicious death at a country house, Detective Inspector Bridget Hart is surprised to find a government minister among the party guests. Her team must navigate powerful interests to find the truth. But in a world of favours, backhanders and corruption, nothing is as it seems and nobody can be trusted.