I wasn't quite sure where this story was going. (I'm still not sure, but there you go.) It was just a oneshot idea that was inspired by an incident the other day, when I rescued a blackbird from the middle of the road; I then handed it over to the vet, and only afterwards realised that they might not be terribly inclined to help it, save to "put it out of its misery". This story is a bit of an antidote to that potentially disastrous one. Anyway, it's shameless fluff, and I hope you enjoy it.

London's network of cabbies was by now used to Sherlock Holmes. He was a friend of nearly all of them, except the ones who were criminals in their spare time, and it was a rare week when at least one of them didn't have to pick Sherlock up from outside his house on Baker Street and rush him off to the scene of a crime. Sometimes, if they had the time, they hung around that area of London, in the hope of adding some excitement to their humdrum routine.

It was because of this that Sherlock Holmes never had to wait long for a taxi. Therefore on this particular day, when Sherlock raced out of his house, coat-tails flying, he found a taxi precisely where he normally caught one, its passenger door open ready to receive him.

To the cabbie's surprise, Sherlock entirely bypassed his vehicle, held out a hand to stop the car that was about to overtake him, and hurried into the middle of the road, before bending down as if picking something up from the tarmac. A few seconds later he waved to let the cars come by, and dashed back towards 221 Baker Street with his hands drawn up to his chest, and a deeply concerned expression on his face.

The cabbie shrugged, called out some unreturned greeting and goodbye to the detective, and closed his door and left.

Sherlock meanwhile pounded up the stairs, opened the door to his flat with his elbow, and placed his cupped hands on the table in front of John's bowl of cornflakes. He was holding a small blackbird.

'He's injured,' he said. 'Broken leg, I think. More your division than mine.'

John's spoon slid from his fingers into the milk. 'It... Sherlock, that's a bird.' He rubbed his eyes. He didn't really function before he had had his morning cup of tea.

The bird looked forlornly up at them both.

'Well?' said Sherlock.

'Hang on, I haven't finished my cornflakes,' said John.

'But this is urgent, John,' Sherlock insisted, still catching his breath.

With a small sigh, John ate the last spoonful of cereal and pushed his bowl to one side. 'I'm not a vet, Sherlock.'

'Humans can't be that different from birds,' countered Sherlock. 'You've told me before that the bone structure is remarkably similar.'

The blackbird opened its mouth a little as if it wanted to contribute to the conversation. John made to take it from Sherlock's grasp, but it wrapped a claw around the detective's finger.

'It likes you,' chuckled John.

Sherlock did not reply to this. He managed to pry the claw from his finger, and handed the little creature over to John, who looked closely at its leg. It was indeed broken, or at least sprained badly – it had probably been struck by a car. The bird did not seem to be in too much pain, but appeared stunned.

'Careful with him,' Sherlock said.

'You know it's a him?' John was surprised. It was easy to tell them apart – male blackbirds are black, and females brown – but this was, of course, a man who had lived blissfully unaware of the Earth's orbit round the sun.

Sherlock did not expand on the matter, and instead watched as John first bathed the blackbird's leg, and then began to inspect it, at last setting it in a splint. John may not have been a vet, but he worked diligently and accurately, as if this was a miniature human: and when he had finished, the bird looked far happier. And, furthermore, so did Sherlock.

John was going to put the bird in a box, but Sherlock insisted that he hold it again. Therefore the bird was placed in his hands, so that the fur was ruffled against his fingers, and he could feel its tiny heartbeat competing with his own. Then he went to sit down in his armchair, and John followed, all the while watching Sherlock with immense curiosity.

Sherlock, he knew, had the instincts of a child. It wasn't unlike him to get possessive, and nor was it unlike him to show a soft side, regardless of how cold he seemed to like to appear. But this was somehow striking. The bird trusted Sherlock: that much was evident. And Sherlock was very much attached to the bird, for he held it perhaps a little tighter than was necessary, and brought it close to his chest, as if fearing that John might take it from him.

John had brought over his cup of tea, and now drank it from the comfort of his armchair, without taking his eyes off his friend. Sherlock did not even seem to notice him. He was staring at the bird, as lovingly as was possible with those cold grey eyes, watching the blackbird's brown eyes settle, and the eyelids flicker. It looked as if it might fall asleep, and Sherlock seemed close to joining it.

There was however something John needed to remind him of, and, though he was unwilling to voice it, he at last said this: 'You can't keep it forever, Sherlock.'

At once Sherlock's eyes flicked upwards to regard him. And though he was well aware of the answer to his question, he said stubbornly, 'Why?'

'It's against the law. If you take in injured animals, you have to release them when they're well again.' His hand went to his laptop, meaning to show Sherlock the particular page about it, but Sherlock nodded, comprehending (if reluctantly), and furrowed his brow. The blackbird looked up at him with a naïve sort of expression.

'But, John,' Sherlock said at length, 'equally, if one releases animals back into the wild after handling them, they can become bewildered, sometimes overly trusting...' He did not want to add that such re-introduction often led to their death.

'Well, yes, that can sometimes happen,' John said lamely.

'But he trusts me,' Sherlock said.

Though it was impossible that the bird had understood his words, it must have absorbed some of the sentiment, because it shuffled a little so that it sat more snugly in Sherlock's hands, and looked at him adoringly.

'Well,' John began, and then released his hold on a sentence that he couldn't finish.

They sat in silence for a few moments, not knowing quite what to say.

'John, when I was younger...' Sherlock knew that John found it hard to imagine him as a child, chiefly because he was still childish, and looked as if he had been an adult-child forever. 'I had a dog. Redbeard – like a pirate. He trusted me... and I trusted him. With my life.'

John furrowed his brow and nodded. He, too, had had beloved pets, and knew the relationship that grew between them and their owners. He had often been tempted to call it Stockholm syndrome, but he knew that there was something deeper and far more beautiful there.

'When he had to be –' Sherlock choked a little. 'He had trusted me, and he watched me even as he left, and I know he thought that I would rescue him if he came into any danger –' His hand went to his mouth, suppressing a dry sob that threatened to leap from his throat. 'He trusted me, John. Don't you see? I hate being betrayed – I hate more being the betrayer.'

'Sherlock,' said John falteringly. 'Sherlock, you're taking this a bit seriously.'

Sherlock stood, still cupping the bird in his hands, and paced to the fireplace and back, before standing at the window looking down at the street. 'And when I get clients, John,' he said at last, 'they trust me. They have to. Their lives are in my hands. When they leave this house, they step at once back into the danger that's threatening them – if it is serious enough, I will make sure that they are out of harm's way.'

John could not say anything to this.

'I am trusted, John, and that is the greatest feeling in the world. You trust me, don't you?'

'With my life,' said John, aware that he was echoing a sentiment of earlier.

'And I would never betray you. Never. That is what separates me from the bad side – there can't exist trust on a side that is composed of evil intent... Put plainly, I detest betraying anyone or anything: and therefore I must keep this bird.'

For a long moment John regarded Sherlock; the detective did not turn round. His eyes were on the very spot where he had found the blackbird. He did not like to think what would have happened if he hadn't got there in time.

'Sherlock, you can't save every life –' John began. Sherlock looked indignant. '– but you can save this one, maybe just for a little longer than the law dictates.'

A smile came onto John's face, and a beaming grin onto Sherlock's.

'I won't tell the RSPB*,' John promised.

And Sherlock, to John's mild astonishment, lifted the bird and planted a light kiss on its beak. The blackbird chattered pleasantly.

He went to sit back in his chair, and put the bird in his lap, and began to stroke it, with a look of infinite happiness on his face. John, across from him, smiled. It was unusual to see Sherlock truly satisfied.

'What are you going to call him?' he asked at last.

Sherlock did not even hesitate. 'Blackbeard,' he said: and both of them burst out laughing.

*Royal Society for the Protection of Birds, the British charity in charge of the welfare of wild birds.

NB. It IS in fact the law to return any injured birds to the wild after they have healed, so please don't use this story as an excuse to become a criminal.