Fieldwork was not Mycroft's forte.

He knew that, and yet here he was. In a damp, unhealthy Serbian cellar, posing as one of Moriarty's generals. Mycroft studied the pattern of the bricks making up the cellar wall. It was not a pleasing pattern. The lack of symmetry bothered him.

In front of Mycroft a prisoner was being tortured.

...

Mycroft was going to have to go to a lot of trouble to find Sherlock, he realised.

He was sitting behind his desk in London. His assistant had brought him a tray of tea the best part of an hour ago and the tea was still there; long-since gone cold. Biscuits also untouched. Mycroft's fingers were steepled under his pale face. Keen eyes studying something that he was seeing in his mind's eye.

Since his brother had been away, things had been… difficult. No-one to bounce ideas off, no-one to run his errands. To start with he'd had regular updates from Sherlock via various operators in Europe, ending with a report from Serbia. And then suddenly nothing. Silence.

And now this. Mycroft scrutinised the documents on the desk. An underground terrorist network operating in London. The threat imminent.

The information Mycroft now had on the Moriarty network was extensive. Sherlock had done his job well. Mycroft knew that MI6 could send in one of their highly-trained agents to infiltrate the Serbian cell with an almost certain possibility of success. The problem was that MI6 were never going to allow any of their highly-trained agents to risk going in to rescue someone with no official status, no official role. Someone who was technically dead, for goodness' sake.

The thought of Mycroft going undercover was ludicrous. Had he run it past anyone else in the department they would have believed it a joke. Mycroft: physically unfit, practically chained to his desk. True, Mycroft was used to turning up in out-of-the-way locations for secret meetings. But always to be whisked away again to safety by a bullet-proof limo. If Mycroft was caught by enemy agents, he could spill enough state secrets to bring down the entire British government. Mycroft knew the powers-that-be would never allow such a liability.

Mycroft's adept mind could see every eventuality of the potential mission. Every possible outcome. Going with no official endorsement, no official backup would be...well, it would be extremely dangerous.

Mycroft's brow wrinkled with distaste at thought of the conditions he would have to endure. There were few hotels that would ordinarily meet his standards. He wasn't used to roughing it. He remembered as a child when he'd stayed away camping with the Boy Scouts. That had been a mistake. He remembered the terrible mud, the camp-fire smoke in his lungs, sleeping on uneven ground. Ugh. Mycroft's fingers unconsciously straightened the items on his tea-tray at the vile thought. Serbia was going to be worse than Scout camp, he imagined.

But bringing Sherlock back was paramount to the safety of the country. It was tactical. It was logical. And the goldfish representing the rest of the security services could not be expected to understand that. And that was why Mycroft had to go. Cold logic dictated it.