Where the Marble Arch stands today in London was once the Tyburn gallows—also known as The Hanging Tree. The walk toward those gallows along Oxford Street and past the Mayfair mansions has a bloody and haunted history as the last trip of the condemned. Some things never change. For both blood and ghosts have returned to those mansions of the super-rich. And it’s up to Peter Grant—England’s last wizard and the Metropolitan Police’s reluctant investigator of all things supernatural—to get to the bottom of the sinister doings.