One thing is for sure: there will be blood.
Unohana has left a letter to her lieutenant Isane, while Zaraki leaves his eye patch for Yachiru to find. In the dark, isolated cave, Unohana and Zaraki start their battle with Unohana easily getting the better of Zaraki with her two sword style. Zaraki is slashed and beat up and Unohana tells him that he's weak. Eventually Unohana disarms Zaraki and stabs him through the throat. Zaraki thinks he is done for, but moments later he is fighting Unohana again. Zaraki isn't sure what happened but decides to focus on the fight instead. Little does Zaraki know, Unohana's plan is for Zaraki to get stronger by sending him cross the boundary the death again and again, and this is a mistake on Zaraki's part and a sin on Unohana's part.
That was a really quick chapter to read through, but it had some very interesting stuff. More interesting than Ichigo and Renji's bizarre adventures through Zero Division palaces thus far, that's for sure. It looks like Unohana's plan is to kill Zaraki and somehow revive him over and over again so that he becomes stronger and stronger. The method of revival though is still a mystery at this point, but Unohana's statement that it's Zaraki's mistake and her sin that Zaraki doesn't just simply die. Obviously the two of them have a lot of history together and I'm looking forward to finding out about it. I hope both will survive this training thing though. It'd be unfortunate if Unohana had to bite the dust so soon after showing how awesome she is.