Victor Dean, an advertising executive, dies after falling downstairs at Pym's Advertising Agency, in London. Wimsey is called in to investigate, as just before his death Dean had started a letter to his employer about strange practices at Pym's. Assuming the name of Death Bredon, Wimsey takes a job in the business, and finds blackmail and a drug pusher. Wimsey and Charles Parker have to fathom London's cocaine trade (and how the staff at Pym's fit into it) before the mystery of Victor Dean's death is solved. Meanwhile, there are more deaths - five in all.