An eloquent glance over his shoulder at Umber as they entered suggested that Sharp's acceptance of the invitation was not prompted by an eagerness to socialize with Abigail Nevinson. The house was warm and comfortably furnished, albeit in a style several decades out of date. There was a brief discussion of milk and sugar requirements, then Abigail waved them into the sitting room and headed for the kitchen. Umber sat down in an armchair by the fire, while Sharp prowled around, inspecting the contents of a bookcase and a china cabinet.

'Has much changed here, George?' Umber enquired sotto voce.

'Nothing's changed at all.' There was a rattling of cups and the singing of a kettle from the kitchen. 'Except Old Mother Nevinson's not weighing down that chair you've parked yourself in.'

'Great. What about Abigail?'

'Fatter and older. Like her brother, I expect.'

'Are you going to tell her – or him – about the letter?'

'Not until I rule him out as the sender.'

'How are you going to explain our visit, then?'

'Simple. I'll say it was your idea.'

A few minutes later, Abigail arrived with tea and biscuits, frowning pensively. She went on frowning as she distributed the cups and plates, then sat down opposite them, looked solemnly at Umber and said, 'I was very sorry to hear about your wife's death, Mr Umber. We both were. It's terrible how that one day all those years ago ruined so many people's lives.'

'Actually, it's on Sally's account that we're here.' Umber launched himself at once on his hastily prepared cover story. 'Since her death, I've wanted to take another look at what happened and see if I can't… resolve some of the doubts she always had about the official version of events.'

'I offered to help,' said Sharp. 'Least I could do.'

'I thought the police had decided that dreadful man Radd was responsible,' said Abigail.

'I don't go along with my former colleagues on that.'

'No? How interesting. Neither does Percy.'

'Oh? What's his theory?'

'You'd have to ask him, Chief Inspector. Percy has so many theories. About so many things.'

'Including the stone circle, as I recall.'

'Oh yes. He's quite the expert on that. It's been virtually a lifelong study.'

'You've always lived here?'

'Well, we used to live in the village proper, of course. But our cottage was pulled down and we were moved over here when Percy and I were children.'

"The Nevinsons go back a long way in these parts, do they?'

'No. But the Bates do. My mother's side of the family. Did, I should say. There are none left round here now.'

'Except you and Percy.'

'Except us.'

'Last of the line.'

'It's turned out that way, yes.'

'Did you ever think of…'

'Marrying? I've had offers in my time, Chief Inspector, I can tell you. None I cared to accept, though. Besides…'

'There was always Percy to look after.'

Abigail bridled faintly at that. It seemed to Umber that she had suddenly realized she was being drawn in a direction she did not wish to take. 'Will you be… speaking to everyone involved in the tragedy?' she asked with conspicuous deliberation.

'If they'll speak to us,' Sharp replied.

"The Halls got divorced, you know.'

'I did know, yes.'

'Mrs Hall – Mrs Questred as is – still lives locally.'

'Do you happen to know where?'

'Over near Ramsbury. It's a picture-postcard house at the bottom of Hilldrop Lane. Swanpool Cottage. Not really what you'd expect her to make do with, pretty or no, but there it is. Her husband keeps a wine shop in Marlborough, so I suppose it's handy, though how she can bear to stick so close to Avebury I don't rightly know.'

'You think she should live somewhere… grander?'

'Well, she did live somewhere grander when she was married to Mr Hall, didn't she? And I suppose he'll have had to pay her a goodly sum to settle the divorce.'

'Do you ever see her?'

'In Marlborough, from time to time. Shopping and such. She doesn't know me, of course.'

'But she'd know Percy?'

'I suppose so. But I'm not sure she'd show it.'

'Maybe she's trying to put it all behind her,' suggested Umber, to an irritated frown from Sharp.

'Maybe she is,' said Abigail. 'No-one could blame her for that.'

'No,' said Umber. 'No-one could.'

Percy Nevinson had still not returned when, half an hour later, Umber and Sharp took their leave. Abigail had noted down Umber's mobile number and assured them she would ask her brother to ring them as soon as possible.

'I'll thank you not to undermine my questioning of suspects in future,' Sharp complained as soon as they were clear of the estate.

'Abigail's hardly a suspect,' said Umber.

'You know what I mean.'

'You were pressing too hard, George. Do you want Percy on the defensive before you even speak to him?'

'I have a feeling he'll be on the defensive anyway. His sister's hiding something. Which means he's hiding something.'

'You don't know that.'

'I sense it. In this game, that's as good as knowing. If not better.'

'If you say so.'

'How many murders have you investigated, Umber?'

'Come off it, George.'

'How many?'

Umber sighed. 'None, of course.'

Sharp nodded. 'Exactly.' And with that he quickened his pace.

Neither Sharp nor Umber looked much about them during this spat. As a result, they did not notice the figure in the telephone box at the corner of the lane that led them down to the footpath back to Avebury. He was a short, tubby man dressed in hiking boots, pale-green corduroy trousers and a faded brown anorak. The brim of a dark-green Tilley hat, worn low, obscured his features. He had his back turned as they passed and appeared as oblivious of them as they were of him.

He shifted his stance once they had reached the footpath, however, and could hardly have failed to see them as they moved ahead. A moment later, he put the telephone down, exited the box and headed into the estate, moving at an anxious clip.

'Where are we going now, George?' Umber asked as they drove out of Avebury past the surviving stones of an ancient avenue that led south from the circle.

'Worried I'll go straight to Swanpool Cottage and antagonize Jane Questred, are you?' Sharp responded.

'Well…'

'Credit me with some sensitivity, Umber. I let her down twenty-three years ago. Badly. If she wrote me that letter, I could hardly complain. Doorstepping her on a Monday morning isn't the way to break the ice. Besides, Abigail only gave us her address to get us off Percy's case. I don't like being manipulated.'

'So, what's the plan?'

'We'll drop in on Edmund Questred's wine shop and ask him – ever so politely – if his wife will talk to us.'

'And if the answer's no?'

'It won't be.' There was the briefest of pauses before he added, 'Unless she's hiding something as well.'

Marlborough was much as Umber remembered it. A gently curving High Street wide enough to turn a coach and four in was flanked by handsome buildings of several eras, mostly in brick, housing a genteel assortment of shops and cafes. They drove in past the teaching blocks and playing fields of Marlborough College, scanned for a parking space – and found one in the centre of the High Street. Almost exactly opposite them, Umber noticed, was the arcaded, tile-hung frontage of the Kennet Valley Wine Company. And Sharp had noticed it as well.