For all those who didn't read the first part I put a summary together.
What happened before
After Kaname has given Zero a little break by letting him feed on his pure blood that retarded the transformation to a Level E Yuuki is outraged as she thinks Zero has transformed into a true vampire. Later they find out he hasn't and still has episodes of blood thirst. Meanwhile Yuuki's relationship to Zero as well as to Kaname has strengthened by an almost kiss by Zero and a proposal by Kaname. Zero is more than jealous. Seeing through Kaname he became aware that Kaname was going to do something to Yuuki. Yuuki however defends her love and runs off. That night Kaname makes Yuuki a vampire, revealing the fact that they are siblings. Soon Rido, their uncle, who is after Yuuki shows up. While Yuuki heads off to fight him Kaname encounters the council and kills all members. Outside at the battlefield Yuuki and Zero meet after a long time. Together they defeat Rido and end up facing each other in another fight.