Novelist John Munting shares, with former public school contemporary and talented painter Harwood Lathom, a rented top floor flat in respectably suburban Bayswater, London.

Creeping downstairs to meet his mistress one night, Lathom encounters the Harrisons' neurotic live-in spinster companion, Agatha Milsom, who mistakes him for Munting in the dark and makes accusations of assault.

Lathom departs for Paris and his portrait of Mrs Harrison, exhibited at the Royal Academy, makes his reputation on the London art scene.

Barton suggested to Sayers the scientific theme crucial to the novel's dénouement, which concerns the difference between a naturally produced organic compound and the corresponding synthetic material, and the use of the polariscope to distinguish between them.

[1] As a practising Christian, Sayers was pleased with the religious-scientific theme offered to her by Eustace, which was based on the idea that the asymmetry of living molecules was an indication of the hand of God in creation.

"This point is made very clear in the lengthy exposition at the local vicar's dinner party, where Munting follows a wide-ranging debate about religion, science and the origin of life.

A keen choral singer in her Oxford University years, Sayers introduces at this point the key theme of Haydn's oratorio The Creation.