Celebration is in the air at Wrexford and Charlotte's country estate as they host the nuptials of their friends, Christopher Sheffield and Lady Cordelia Mansfield. But on afternoon of the wedding, the festivities are interrupted when local authorities arrive with shocking news: a man has been found murdered at the bridge over King's Crossing . . . his only identification an invitation to the wedding.

Lady Cordelia is horrified when the victim is identified as Jasper Milton, her childhood friend and a brilliant engineer rumored to have discovered a revolutionary innovation in bridge design. That he had the invitation meant for her cousin Oliver--who never showed up--stirs unsettling questions. Both men were involved in the Revolutions-Per-Minute Society, a scientific group dedicated to making radical improvements in transportation throughout Britain. Is someone plotting to steal Milton's designs? And why has her cousin disappeared?

Wrexford and Charlotte were looking forward to a peaceful interlude in the country, but when Lady Cordelia resolves to solve the mystery, they offer their help, along with that of the Weasels and their other unconventional inner circle of friends. The investigation turns tangled, and soon all are caught up in a treacherous web of greed, ambition, and secrets. And when the trail takes an unexpected turn, Wrexford and Charlotte must decide what risks they are willing to take with their family to bring the villains to justice . . .