Yuuki starts to remember parts of her forgotten past. and wants to find out about her real family. As she begins to unravel the secrets that where hidden from her to protect her, she must choose between Kuran Kaname, the one she owes her life to, or Kiryuu Zero, whom she has always wanted to protect
Yuuki wants to know more about her true family and her forgotten past and starts a research. The secret will be revealed. Yuki, Kaname and Zero will show the begining of a new mystery and a forbidden love.
I think this season is better than the last one because it has more action and explains about Kaname's and Yuki's relationship, it also tells you more about Zero's character. Season two introduces the new evil character it's surprising who it is. If you like the first season you'll definitely like season 2.