Becoming lost in Hueco Mundo should be a death sentence for a shinigami. But every once in a while, hope can be found in the darkest and strangest of places. (Canon divergence, Starrk and Ukitake centric)
After the Winter War, the surviving espada are captured and put in kido stasis until a new Central 46 can determine their fate. As time drags on, they are all but forgotten and Shunsui finds himself feeling guilty for his part in Starrk's plight and speaking with the primera's imprisoned form...unknowing that Starrk can see and hear everything that is going on around him.
Disillusionment comes in many forms. In a world where Zhao decides to take a more personal involvement in the young prince's murder, and Zuko receives proof that such an assassination attempt could not happen without the Fire Lord's approval, his journey to capture the avatar comes to a painful, premature end.
It's a bad idea to play with artifacts you don't understand...such as the hogyoku. Aizen really should have taken this into account before he accidentally sent his primera (and his vizard opponents) to a different dimension. Specifically, a dimension eighty years in the past, within Seireitei. Starrk finds the situation inconvenient. Love and Rose feel a bit more strongly.
In the frozen pause between incident and reaction during a coronation that should have been cause for celebration, two sisters realize their world is crumbling and come to very different conclusions as to who is responsible.
After the battle of Karakura Town, our favorite simple shopkeeper and part time mad-scientist finds the mostly-dead primera buried beneath the rubble and reacts...characteristically. Starrk is not amused. Urahara is intrigued. (Occurs immediately post-Winter War)
Yammy's climb through the ranks is unorthodox at best. The other espada really could not care less.