Here, I'll save you reading 4 months of the manga:
1. Aizen and co. fight the captains, seemingly overpowering them with ease.
2. The captains in HM walk around in a fucking tizzy wringing their hands and healing people.
3. Urahara and the vizard show up to help fight Aizen. Gogo gadget espada release.
4. Grimmjow is fixed up, and agrees to rip a tunnel back to Karakura for them, on the basis that he's a traitor for attacking another espada and Aizen would get rid of him for losing anyway. Just as they're about to leave, Ulquiorra comes back from his void dimension.
5. Ichigo and co. get back from HM just in time to watch Aizen finish making the key and head off to the king's realm. CUE FINAL ARC.