Celebration is in the air at Wrexford and Charlotte's country estate as they host the nuptials of their friends. But the festivities are interrupted when the local authorities arrive with news that a murdered man has been discovered 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 who is rumored to have discovered a revolutionary innovation in bridge design. That he had the invitation meant for her cousin Oliver, who never showed up for the wedding, stirs a number of unsettling questions. Both men were involved in a scientific group dedicated to making radical improvements in transportation. Is someone plotting to steal Milton's designs? And why has her cousin disappeared?

Wrexford and Charlotte were looking forward to spending 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 inner circle of friends. The investigation turns tangled and soon all of them are caught up in a treacherous web of greed, ambition, and dangerous secrets. And when the trail takes a shocking turn, Wrexford and Charlotte must decide what risks they are willing to take with their family to bring the villains to justice . . .