It wasn't often James Batchelor had the house to himself, but just sometimes he could persuade Matthew Grand that the Muse must take precedence over finding lost dogs and other footling pursuits. Today was such a day. When he had first had the news of the death of Charles Dickens he had, like most of the English-speaking world and a decent proportion of the rest, been stunned. Yes, the old boy wasn't a spring chicken and yes, he had been ill on and off for a while, as reported in the Telegraph but ... dead? It didn't seem possible that that great heart had stopped beating, that there would be no more deaths to wring men's withers, no more ghosts to haunt their nights. Batchelor had been working on his Great British Novel for some time and it wasn't going well. It seemed to him that every time he imagined a plot twist which would make his fortune, so it would appear in some weekly sheet and he would have to begin again. He had stopped talking about his opus; the walls clearly had ears. Grand reminded him sardonically from time to time that this happened to him because he couldn't actually write for taffy, but Batchelor maintained a lordly silence and retired to his little garret under the eaves whenever he got a moment.

Their new housekeeper, Mrs Rackstraw, had words to say on the subject of the garret, and some of them were fair enough, as Batchelor agreed when he was feeling generous. She rightly pointed out that there were many rooms much more congenial on the ground, first and even second floors. So why did she have to haul herself up another flight of stairs every time she needed to speak to the young gentleman? The best houses had bells for that sort of thing. Her cousin Mildred's eldest knew of a parlour maid in Stoke Newington who never had to put her foot to the floor unless her particular bell rang. Mrs Rackstraw had no truck with his answer that he couldn't write except in total solitude; when she was in a proper bate, as her friends called it, or an apoplexy, as her doctor tended to refer to it, she would go so far as to spit. But she could cook like an angel, cleaned the house as if the devil himself were after her and – perhaps most importantly – she hated and abhorred cats with an unusual fervour. Grand and Batchelor had not disliked Mrs Manciple, their previous housekeeper but one, but in the end her cat obsession had reached a level that no normal household could sustain. After she was carted away to the Colney Hatch Asylum, where she still lived in the lap of luxury, courtesy of Matthew Grand, it had taken them months to find homes for all of her pets. They seemed to be self-sustaining; as soon as three went to good homes, another had four kittens. But eventually they were all gone and, after a brief sojourn with a butler and a chef in charge, during which time they both gained a stone – or, rather, Batchelor gained a stone and Grand gained fourteen pounds – they found Mrs Rackstraw, who had many failings, but suited them most of the time.

Happily, on this beautiful June morning, marred only by the fact that Dickens was still dead, Mrs Rackstraw was in a moderately good mood. In anyone else it would have looked like a foul temper, but Batchelor was used to her little ways, so ignored most of the crashing, banging and foul oaths that preceded her up his little winding stair.

The door to the garret crashed back, leaving a deep gouge in the plaster behind it. Why they kept having it repaired, Batchelor never knew – it would only be there again in a few weeks.

'There's a sailor downstairs wants you.'

Batchelor looked up, another golden phrase dribbling from his brain, another gem forever lost to posterity, like King John's jewels in the Wash. 'I beg your pardon, Mrs Rackstraw. Did you say a sailor?'

'That's what I said,' she said, taking another step into the room. The climb had made her a little breathless, so she did no more. 'I asked him his name, like you always say I have to, though for the life of me I don't know why I bother. They always says it again when you come in. Or say it's personal and none of my business. I asked him his name and he says "Tell him I'm a sailor." So here I am, telling you. There's a sailor downstairs wants you.'

'Does he want to consult us professionally?' Batchelor was excited. A sailor could have any number of intriguing problems he needed them to solve. Missing cargo, perhaps. Piracy on the High Seas. Embezzled naval funds. Man overboard – now, that would be a challenge worthy of their mighty intellects.

'Don't know,' Mrs Rackstraw said, and Batchelor almost heard the unspoken 'don't care'. 'He'd go to the office, wouldn't he?'

Sometimes the woman came out with bursts of logic, and in this case she couldn't be faulted. Batchelor got up. There was clearly no way in which this present puzzle would be solved unless he went downstairs and confronted this sailor. 'How old is he, Mrs Rackstraw?' he asked, his foot on the second stair from the top. There would be little point, after all, in going downstairs to interview some cabin boy or other lowly seafarer. Time, in the largest city in the world, was money. And Grand and Batchelor had a fixed price for their services that was hardly, as Grand would say, bargain basement.

'Ooh, I dunno,' she said, pursing her already very pursed mouth. 'I'm no good on ages ... forty? Fifty? Sixty? Could be anything.' She turned on the stairs and looked up at Batchelor. 'He's a bit ...' she waved her hand in front of her face, vaguely sketching in details. 'Blobby.'

'Mrs Rackstraw! That's not a polite way to describe our guests.'

'No, but you wanted to know ...'

They were now on the landing of the first floor and Batchelor raised an admonitory finger. 'Ssshh! He'll hear us.'

'No, he won't,' she said, crossly. She didn't use so much breath going downstairs, so she could give her temperament freer rein. 'I put him in the drawing room.'

'Even so ... blobby, you say?'

'Yes.' She screwed her face up at him. 'Like a ... what's that animal?' She set off down the final flight of stairs. 'That animal, you know the one?'

By now Batchelor could hardly wait to meet his visitor. A sailor who looked like an animal. He was almost sure he could actually include such a creature in his Great British Novel.

Mrs Rackstraw reached the drawing-room door first and flung it open with her customary élan, remembering the animal as she did so. 'Gorilla!' she cried and stepped back.

The visitor half rose from his chair with commendable calm following her rather unusual introduction and turned to his host. 'James!' he said. 'You look well. It's good to see you again. How is the writing coming along?'

Batchelor covered the distance to the man's outstretched hand in three enormous strides. Everything fell into place. The carefully Macassared hair, the Savile Row suit, the air of the swell, the nose; especially the nose. It wasn't a sailor who looked like a gorilla at all. 'Mr Sala!' he said, shaking his hand enthusiastically. 'Mr George Sala! How can I help you?'

Mr George Sala's smile vanished instantly. 'Dickens,' he said.

'Yes.' Batchelor nodded solemnly. 'Tragic. Tragic. You worked for him, didn't you?'

Sala bridled a little. 'With, dear boy, with. To me, he was everything. In him I have lost all that I most revered and loved.'

'Oh, George,' Batchelor...