Dean Thomas became an auror and was assigned to be the magical guard of the Royal Family. There always had to be one wizard guarding the muggle prime minister and one guarding the Royal Family. Between his dad having been a muggle army officer and his excellent track record, he was the perfect candidate for the job. He didn’t think that it would be a particularly difficult mission beyond actually protecting the Royal Family. He knew how to dress and act like a muggle, he knew how to blend in a group of soldiers and his handler, Ron, would never lead him astray.
Then it started. He noticed it the first time when he felt his neck tense up in a way it hadn’t since he was on the run, but Dean dismissed it as paranoia because the war was over and there were no more Death Eaters. Any “blood-purist” groups were arrested before they had the chance to do anything. Then he felt it again. Then another time. The fourth time he noticed the uneasy stare of the man behind the camera he started to consider his options and what he could do next. Undercover meant that he couldn’t contact his friends and family for the duration of his mission, so that option was out. Embarrassment stopped him from telling Ron or the Head Auror, Harry. Though they were his friends and he’d fought alongside them in the Battle of Hogwarts, he always felt weak complaining to those two. They had been fighting pure evil with Hermione since they were eleven. Every year finding new ways to endanger their lives for the sake of others. They would help but he couldn’t go to them.
Then he heard about him. The deerstalker detective. The man’s abilities had garnered him much fame in both the Wizarding and muggle worlds. He had successfully faked his own death for two years with no one doubting him at all. Not only that but the man’s skills were truly astounding. Something not even wizards could achieve because it wasn’t magic no matter how many times muggles claimed that it was. It was simple deduction in order to solve mysteries. And Dean had a mystery that needed solving.
So Dean Thomas made a decision, he would contact Sherlock Holmes for help.