'And you have changed your minds. Or you have changed her mind. Or she yours. Yesterday you said you would back me without question.'

'I know what I said. And it is not a matter of my changing Connie's mind, or her changing mine. We have discussed it, and we are agreed.'

'I congratulate you.'

'Arthur, let me put it this way. Yesterday we spoke to you with our hearts. You know how Connie loves you, how she always has. You know my enormous admiration for you, how proud I am to say that Arthur Conan Doyle is my brother-in-law. That's why we went to Lord's yesterday, to watch you with pride, to support you.'

'Which you have decided no longer to do.'

'But today we are thinking, and speaking, with our heads.'

'And what do your two heads tell you?' Arthur reins his anger back to mere sarcasm. It is the best he can do. He sits four-square in his chair and watches Willie dance and shuffle in front of him, as he dances and shuffles his argument.

'Our heads – our two heads – tell us what our eyes see and our consciences dictate. Your behaviour is… compromising.'

'To whom?'

'To your family. To your wife. To your… lady-friend. To yourself.'

'You do not wish to include the Marylebone Cricket Club as well? And the readers of my books? And the staff of Gamages emporium?'

'Arthur, if you cannot see it, others must point it out to you.'

'Which you seem to be relishing. I thought I had merely acquired a brother-in-law. I did not realize the family had acquired a conscience. I was not aware we needed one. You should get yourself a priest's robe.'

'I do not need a priest's robe to tell me that if you stroll around Lord's with a grin on your face and a woman who is not your wife on your arm, you compromise that wife and your behaviour reflects upon your family.'

'Touie will always be shielded from pain and dishonour. That is my first principle. It will remain so.'

'Who else saw you yesterday apart from us? And what might they conclude?'

'And what did you conclude, you and Constance?'

'That you were extremely reckless. That you did the reputation of the woman on your arm no good. That you compromised your wife. And your family.'

'You are a sudden expert on my family for such a johnny-come-lately.'

'Perhaps because I see more clearly.'

'Perhaps because you have less loyalty. Hornung, I do not pretend the situation is not difficult, damned difficult. There's no denying it. At times it is intolerable. I do not need to rehearse what I said to Connie yesterday. I am doing the best I can, we both are, Jean and I. Our… alliance has been accepted, has been approved by the Mam, by Jean's parents, by Touie's mother, by my brother and sisters. Until yesterday, by you. When have I ever failed in loyalty to any member of my family? And when before have I appealed to them?'

'And if your wife heard of yesterday's behaviour?'

'She will not. She cannot.'

'Arthur. There is always gossip. There is always the tattle of maids and servants. People write anonymous letters. Journalists drop hints in newspapers.'

'Then I shall sue. Or, more likely, I shall knock the fellow down.'

'Which would be a further act of recklessness. Besides, you cannot knock down an anonymous letter.'

'Hornung, this conversation is fruitless. Evidently you grant yourself a higher sense of honour than you do me. If a vacancy occurs as head of the family, I shall consider your application.'

'Quis custodiet, Arthur? Who tells the head of the family he is at fault?'

'Hornung, for the last time. I shall state the matter plainly. I am a man of honour. My name, and the family's name, mean everything to me. Jean Leckie is a woman of the utmost honour, and the utmost virtue. The relationship is platonic. It always will be. I shall remain Touie's husband, and treat her with honour, until the coffin lid closes over one or the other of us.'

Arthur is used to making definitive statements which conclude discussions. He thinks he has made another, but Hornung is still shuffling about like a batsman at the crease.

'It seems to me,' he replies, 'that you attach too much importance to whether these relations are platonic or not. I can't see that it makes much difference. What is the difference?'

Arthur stands up. 'What is the difference?' he bellows. He does not care if his sister is resting, if little Oscar Arthur is taking a nap, if the servant has her ear to the door. 'It's all the difference in the world! It's the difference between innocence and guilt, that's what it is.'

'I disagree, Arthur. There is what you think and what the world thinks. There is what you believe and what the world believes. There is what you know and what the world knows. Honour is not just a matter of internal good feeling, but also of external behaviour.'

'I will not be lectured on the subject of honour,' Arthur roars. 'I will not. I will not. And especially not by a man who writes a thief for a hero.'

He takes his hat from the peg and crushes it down to his ears. Well, that is that, he decides, that is that. The world is either for you or against you. And it makes things clearer, at least, to see how a prissy prosecuting counsel goes about his business.

Despite this disapproval – or perhaps to prove it misconceived – Arthur begins, very cautiously, to introduce Jean into the social life of Undershaw. He has made the acquaintance in London of a charming family called the Leckies, who have a country place in Crowborough; Malcolm Leckie, the son, is a splendid fellow with a sister called – what is it now? And so Jean's name appears in the Undershaw visitors' book, always beside that of her brother or one of her parents. Arthur cannot claim to be entirely at his ease when uttering sentences such as, 'Malcolm Leckie said he might motor over with his sister', but they are sentences that have to be uttered if he is not to go mad. And on these occasions – a large lunch party, a tennis afternoon – he is never entirely sure his behaviour is natural. Has he been over-attentive to Touie, and did she notice? Was he too stiffly correct with Jean, and might she have taken offence? But the problem is his to be borne. Touie never gives an indication that she finds anything amiss. And Jean – bless her – behaves with an ease and decorum which reassures him that nothing will go wrong. She never seeks him out in private, never slips a lover's note into his hand. At times, it is true, he thinks she is making a show of flirting with him. But when he considers it afterwards, he decides that she is deliberately behaving as she would do if they knew one another no better than they were pretending to. Perhaps the best way to show a wife that you have no designs on her husband is to flirt with him in front of her. If so, that is remarkably clever thinking.

And twice a year, they are able to escape to Masongill together. They arrive and leave by separate trains, like weekend guests who just happen to coincide. Arthur stays in his mother's cottage, while Jean is lodged with Mr and Mrs Denny at Parr Bank Farm. On the Saturday they sup at Masongill House. The Mam presides at Waller's table, as she always has, and presumably always will.

Except that things are no longer as simple as they were when the Mam first came here – not that they were ever simple then. For Waller has somehow managed to get himself married. Miss Ada Anderson, a clergyman's daughter from St Andrews, came to Thornton Vicarage as governess, and, so village gossip asserts, instantly set her cap at the master of Masongill House. She succeeded in marrying the man, only to find – and here gossip turned moralizing – that she could not change him. For the new husband had no intention of letting mere matrimony alter the way of life he had established. To be specific: he visits the Mam as often as he ever did; he dines with her en tête-à-tête; and he has a special bell installed at the back door of her cottage, which only he is allowed to ring. The Waller marriage does not bring forth children.