Her world has fallen apart, but it seems to go on perfectly well around her. Simon’s charwoman, Mrs Muckle, departs for Gloucester, where she means to stay until Twelfth Night. Miss West is prevailed upon to confess, and she does it with aplomb: admitting not just to the murders of Mr Meers and Pearl, but to those of Mr Boyle, Ned and even Commander Hargreaves, despite the lack of evidence tying her to the crimes. She has the fame, if not the freedom, she always desired.

No one dubs her the Mesmerising Murderess.

The only transgression Miss West is not denounced for is the abduction of Cedric, for Cedric was never there to kidnap; he was trampled beneath the hooves of the horses fourteen years ago. It was the brandishing of his new hoop and stick that caused them to bolt.

Agnes tries to accept this, tries to understand that her recent memories of the boy are entirely false. But sometimes she could swear she hears the click, click of his toy rolling down the street at night. Or perhaps it is the sound of a ghostly carriage, wheeling Constance to her doom over and over again.

‘Am I quite mad, Simon?’ she asks, as he sits up with her by the light of a single candle. ‘Have I lost my mind entirely?’

He is always emphatic. ‘No. You knew about their deaths and accepted them for over a decade. It was only the pneumonia of ’52 that … unsteadied you. You were so very ill, Miss Darken. Near to death. I had half-steeled myself to lose you …’ He breaks off, recovers himself. ‘When you were past the danger, you seemed to … reset, somehow. You saw them. And you were so weak, I did not dare to retard your progress by breaking your heart all over again.’

She surveys Constance’s bedroom. The red and yellow quatrefoil paper that her sister chose still hangs from the walls. Her four-poster bed remains, without curtains, as was her preference. The mahogany dressing table and mirror stand just as she left them. It seems Agnes is not the only person who has been afraid to confront the past.

But she does face it, in stages.

Simon pays the subscription for them to drink water from the Hetling Pump. It is still within sight of the abbey, but at least it is a little further away from her house at Orange Grove than the Grand Pump Room. She could not bear to be in such close proximity to the scene of the Accident – not yet.

She sips the tepid, mineral-tasting liquid, trying to make her peace with that element. The memory of the river rushing into the carriage, seeking to engulf her, is now painfully clear. It might not have succeeded in taking her life, but it certainly swept her old self away.