Fresh from a 34-day, 18-city tour of England, professional musician and amateur sleuth Jason Davey accepts an invitation from a fan, Marcus Merritt, to meet at Level 72 of The Shard to sign one of his band's programs. Marcus hands him the booklet, then leaps to his death from the open viewing platform. Thus begins a week-long quest, during which Jason is tasked with retrieving a stolen collection of scores by England's most famous composer, Sir Edward Elgar. Marcus shared Elgar's love of eccentric puzzles and games, and the challenging clues he's assembled for Jason seem to mirror the 14 themes in Elgar's renowned Enigma Variations. Jason's journey takes him to Derbyshire and then back to London, and a four-hour walking tour of Soho's lost music venues where, in Denmark Street, he faces a life-threatening battle with two adversaries: a treacherous Russian gangster who is also hunting for the stolen collection, and Marcus's sister-who holds the key to a decades-old mystery involving a notorious London crime lord's missing daughter.