She keeps her eyes trained straight ahead, reluctant to let them wander off and follow shadows. The music from the Assembly Rooms swells outside as she descends. It is sacred, choral, with the deep thrum of an organ beneath.

The consulting room door is unfastened. Agnes slips inside with ease. Her candle flame sparks on glass domes and slides over the gilt tooling on the spines of the books. She lights the lamp upon the desk, illuminating a circle of walnut wood.

Even now, the air is leavened with the scent of carbolic soap.

There are no bottles or medicines in sight. Where in this large room would Simon keep the keys to his cabinets and drawers?

She spies two inkpots standing on the left-hand corner of the desk. Picking each up in turn, she shakes them beside her ear. Metal tinkles in the second one. As she suspected, it is empty and washed out to hide a small brass key: a very simple ruse. Simon has become too used to living alone.

Down the street, the music soars. Morpheus tilts his head comically each time the organ surges into life. She listens, absent-mindedly unlocking the drawers one by one. The single key opens them all. How little Simon must have to hide.

She pulls out the first drawer. It reveals an almanac and newspaper clippings advertising vacancies for medical officers at the workhouse. Simon has scribbled names upon them – no doubt they are people he means to recommend for the positions. She sifts through orders to apothecaries. Under them is a glass vial with Oil of Vitriol written on the side.

In the second drawer she finds only a box of matches and some sticks of sealing wax. Where can the laudanum be? She opens another, finds a whole sheaf of letters tied up with string. Most are from other medical men, detailing cases and sharing news; she notices some from Scotland. They must be the doctors Simon studied with.

She gazes over the names. One occurs more frequently than the others: Tobias Dudfield.

The organ in the Assembly Rooms reaches a crescendo. Agnes yawns and a letter slides from the pile, landing directly beneath the light of the glass chimney.