She felt compelled to play a part in clearing Dr Simpson’s name, for reasons she could not rightly articulate. She had told herself that it was imperative she accompany Raven so that Dr Simpson’s plight was not forgotten in Raven’s eagerness to pursue his own agenda. However, she could not deny that a part of her sought an excuse to leave the house. Time with Archie was increasingly bittersweet. He was weakening before her eyes, and every moment spent with him carried the promise of pain to come. God forgive her for thinking so, but there were times when she could not bear it.

She heard Raven let out a frustrated sigh as they rounded a bend in the road and a neat little cottage came into view, sitting in isolation amidst a well-tended garden with a view of the Forth.

‘Something irks you?’ she asked.

‘This does not look like the kind of home a nurse could afford to rent.’

‘Perhaps she has a husband who earns a good deal more,’ Sarah suggested. ‘There are some men who are happy for their wives to work, after all.’

She enjoyed landing this blow upon him, but her pleasure was tempered by it returning her thoughts to Albany Street, where perhaps she ought to be right then.

‘A woman married to such a man would not choose to work as a nurse, believe me,’ Raven replied. ‘Any more than you would choose to keep working as a housemaid.’

They had found three listings for ‘M. Dempster’ in the Post Office directory, and had come straight from the first one, who had turned out to be a retired book-keeper in Abbey Hill. From Raven’s misgivings about this cottage, it appeared he believed their quest would take them all the way to the third address, in Leith.

‘We have come this far, so we might as well enquire,’ Sarah reasoned.

‘Very well,’ he responded, with little enthusiasm.

The cottage was set back from the road. Sarah thought she saw a flash of movement at one of the windows as they approached, but a cloud of blackbirds had flown past at the same time and she dismissed it as merely a reflection.

Raven rapped on the door, his knuckles firm but not peremptory, as though aware he had little right to be disturbing anyone. He still had not developed the self-importance of the typical professional gentleman, a trait she found endearing in him.

They waited in vain for a response, throughout which time Sarah became more convinced that the black flash in the window had indeed been birds.

‘Do you remember what she looked like?’ Sarah asked, it occurring to her that if she was disinclined to receive them, this Mary Dempster could very easily deny who she was, and they might be none the wiser. Sarah had once learned a harsh lesson concerning an individual presenting himself as someone he was not.