Prompt from Hades Lord of the Dead: common thread.
It was only the merest chance that saved my Watson's life.
I had been working for weeks on the case of the Barghest diamonds, growing ever closer to the mastermind behind the theft. I had received threatening messages, but paid them no mind. Watson was running his own practice at the time and spent most of his time there, and my own safety had never been much of a concern.
I had been down by the docks, following one of the men who I knew to be part of the gang behind the crime, when he met with a compatriot I did not recognise. The man was wearing a familiar scarf - familiar, for the last time I had seen its like had been around Watson's neck. The scarf was made out of common material, with nothing to say it was not merely a duplicate to Watson's, but I would not be easy until I was certain.
I left the two men and journeyed to Watson's practice, where his secretary was quite surprised to see me. "Dr Watson left yesterday afternoon," she told me. "He said he was going to see you, and not to expect him back for a few days. Dr Ferguson has been taking his patients. They have an arrangement, you see."
I thanked her for the information, and hurried to Scotland Yard. I knew where the gang's hideout was, and though I still did not have the proof they had stolen the Barghest diamonds, I would not risk Watson's life by delaying. I still shudder to think how close it came, arriving only seconds before the men executed Watson as a warning to me.
I lost my fee, for though the criminals were tried and convicted on charges of abduction and attempted murder, they did not reveal where the diamonds where, but the money was nothing compared to what I would have lost if Watson had died that day.