The year is 1703, and Matthew Corbett - professional problem solver - is missing. Last seen by his friends in New York before he departed on a lucrative, seemingly straightforward mission for the Herrald Agency in Charles Town, he’s been too long absent. His comrade-in-arms Hudson Greathouse has an increasing sense the young friend he thinks of as a son must have met with some unexpected peril.

Following his hunch, Greathouse retraces Matthew’s steps only to find him first presumed dead, then accused of murdering a young woman and apparently en route to London with a devious Prussian count last encountered on Professor Fell’s Pendulum Island. Little does he know that Matthews’s circumstances are growing worse by the second. For when Matthew arrives in the bustling squalor of Londontown, he’s come shackled, charged for the murder of Count Anton Mannerheim Dahlgren. No matter the lack of body, presumed lost to the ocean. He soon finds himself locked up in the infamous Newgate prison, and has drawn the interest of a mysterious mask-wearing vigilante accused of several gruesome murders. Greathouse and the woman Matthew loves, Berry Grigsby, travel across the high seas to England to aid their friend, but it is impossible to know whether they will reach him in time to save his life.