Author's Note: I do not own Bleach or its characters. This is wildly AU.
For Want of a Nail
Sosuke Aizen was very good at plotting and planning. He was even good at adapting his plans to unforeseen events and changes. However, while he had planned for almost every possible contingency and outcome, there was one thing that he forgot to plan for. Aizen really couldn't be blamed for this. It wasn't the sort of thing that any one would have thought of, and some people had gone to great lengths to keep people from thinking of the idea. And yet, this one unplanned for event would change everything.