(from ebookjapan):
Mayumi, a girl who grew up in an orphanage, is adopted by a zoologist in a respectable house. However, the real purpose of the scholar was to carry out a forbidden animal experiment to implant a monkey brain into Mayumi's head...!　When Mayumi discovers the fact that she has been implanted with a monkey brain, she launches an attack on the scholar's family for revenge and in search of a human brain!　And then Mayumi's real mother arrives...?　The quintessence of Koga horror, where human fear and parent-child sadness are mixed!