Disclaimer: I do not own anything relating to the BBC or Sherlock series.
This story has a loose base in the song "Matchbox" as preformed by The Beatles.
Chickens are filthy, but Sherlock prefers them over sheep. They don't smell as bad, however dusty they may be. He wrinkles his nose and throws his arms over his head, attempting to draw the farmers attention and make it obvious that he is in need of a lift. The farmer pulls his truck onto the shoulder and beckons Sherlock to his window.
"¡Gracias, señor! No tengo nada de dinero, pero, por favor, sólo tengo que llegar al proximo pueblo. Puedo darte algo de gasolina cuando llegamos." ("Thank you, sir! I don't have any money, but, please, I only need to get to the next town. I can give you some gasoline when we get there.")
The farmer motions to the back of the truck and Sherlock nods in faux-appreciation before clambering over the wooden tailgate into the hay-strewn bed of the truck. And into a flapping, feathery mass of hens.
Sherlock settles himself against the hodgepodge wood planked side of the open topped box that comprises the back of the truck as the farmer pulls it away from the shoulder and continues up the road. Sherlock didn't care for using the Galician accent yet. It still felt thick on his tongue and he didn't like having to mispronounce words in order to fool the locals into thinking he was from here. It was easy, yes, but he didn't like it. His appearance—dark hair, fair skin and pale eyes—was not distinctive here, really. Only his height set him apart, but he could curve notice of that by hunching his shoulders and walking with his knees slightly bent. He looks down at his legs, stretched out before him so that his knees can be fully extended for now, and notices that a matchbox-sized hole has appeared above the left knee of his practical khaki pants. People must think he's a vagrant with his haggard appearance, blood seeped into his clothes in a few places, both his own and that of others.
Sherlock shrugs to himself, thinking that that plays into his invisibility.
He's got a cigarette tucked behind his right ear and finds himself wishing for a lighter, a match, a bloody striker, anything to get it lit. But, alas, he's got no matches, simply a long way to go. As he bumps down the road in the back of the farmer's truck he thinks about how far from home he is. He's not got a centimo on his person, and not much more than that stashed away were he can get it. Lucky he knows a man who owes him a few favors in the suburbs they're about to enter.
Mycroft has refused to help with anything but the facilitation of information about John. To make Sherlock guilty, the ex-detective suspects. Mycroft disapproved of this plan at its conception. Sherlock would not be moved. He had known that this was the only way to ensure their safety. Sherlock would live as a migrant for as long as it took, only to keep them—John—safe.
But Mycroft's last communiqué, related through a hardly believable beer-maid in a Brussels pub two months ago, told of John's poor health and mental state due to a melancholy cause by Sherlock's death. So Sherlock questioned whether everything he's done, as it turns out, might be wrong. Was there some other way he could have accomplished this? With John at his side, perhaps? No, he knows. That is unthinkable. But still, he knows also that what he's done is not exactly right, either. And so he's never happy anymore, without John, because everything he ever did was wrong, for all the right reasons.
Since then he's continued to question. He asks himself why John was always so alluring to him. If John didn't want to pursue anything, why did he hint and flirt and care? Why couldn't he just leave Sherlock alone in misery?
Sherlock pushes these thoughts away, fruitless as they are, and sets his mind to the more pertinent problem at hand—getting his cigarette lit.