Change is the only sure thing. Shinichi has recovered from near death, but at the cost of more of his original, human body, which Migi had to replace. The two have also learned that they can work together, destroying the parasite that killed Shinichi's mother. But so much remains unknown. What are the limitations of Migi and Shinichi's shared body? Why can the fully-human girl Kana detect Shinichi's presence, as a prey animal detects a predator? And finally, most importantly, what is the ultimate goal of the cunning and ruthless parasite Ryoko?