In hindsight, the solution was obvious. It was the one time Watson had solved the case before I had. He teased me about it for days. And it was very obvious. I don't know why I didn't see it. I must be losing my touch. Mary finally told him to shut up about it. I was very grateful. But in hindsight, the solution was obvious. Eh, I'm getting old. Mycroft would have laughed so hard. I'm almost 80 now. My croft died a few years back. My brain is getting dumber and dumber the older I get. I'll have to retire. In hindsight, it was obvious...