A 221B (221 words, with the final word beginning with 'b')
This story requires knowledge of the events of "A Study in Pink".
Proper Genius
Sally always said he would end up becoming a killer through sheer boredom.
When he paces around restlessly with nothing to do, his best and only friend watches him with concern and does his best to keep him distracted and busy; and he knows that his brother worries about him, constantly.
It's hard being a genius, with a mind that never stops working even when it has nothing to work on. The frustration of knowing he is smarter than everybody around him – that there's nobody with whom he can spar on an equal level – makes him want to scream with rage sometimes.
And then Sally divorces him and takes away his beloved children, his best friend gets married and moves abroad, and his brother's busy with his own work. Then the diagnosis of the aneurism comes, and now he doesn't care any more and all he wants to do is to outlive other people. Everyone's so stupid – they deserve to die. He hears whispers about the mysterious "Moriarty" and finally tracks him – or them? – down and is put on the path to a less boring finale to his life.
But though he thinks he can see how everything will unwind, like a map inside his head, even he doesn't have the faintest idea that it will all end with a bullet.