The seal on a youkai castle is taken off by Nezumi-otoko [Rat-man] and the youkai from the castle requests children from a village to be given to the castle once a month to turn them into youkai. Kitaro happens to be walking by and offers to help. Kitaro asks to borrow one girl to be bait for the bad youkai. Nezumi-otoko comes to get the girl which surprises Kitaro because they know each other...