Edgar Allan Poe is an American boy in England, a child standing on the edge of mysteries. In 1819, two Americans arrive in London. Soon afterward a bank collapses, a man is found horribly mutilated on a building site, another goes missing in the teeming stews of the city's notorious Seven Dials district, a deathbed vigil ends in theft, and an heiress flirts with her inferiors. All the while, Poe's young schoolmaster struggles to understand what is happening before he and his loved ones are destroyed. But the truth, like the youthful Poe himself, has its origins in the New World as well as the Old—in a bitter episode of corruption during the War of 1812.

With settings ranging from the coal-scented urban jungle of late Regency London to the stark winter landscapes of a rural Gloucestershire, An Unpardonable Crime is a multi-layered literary murder mystery, a historical novel, and a love story. In addition to shedding fascinating light on Edgar Allan Poe, the book is a fast-paced suspenseful tale, filled with shocking revelations.