Kagome learns that Inuyasha is a half demon, born of a human mother and a dog demon. Inuyasha's half brother Sesshomaru appears, looking for the tomb of their father. In order to manipulate Inuyasha, he brings Inuyasha's dead human mother with him. But the woman turns out to be a demon known as a muonna.

The muonna makes Inuyasha reveal the location of his father's grave. Sesshomaru removes Inuyasha's right eye (the black pearl) and opens the entrance to the grave. Kagome is angered by Sesshomaru's cruelty. She goes with Inuyasha after Sesshomaru. Inside their father's tomb is a memento of Inuyasha's father, the sword Tetsusaiga.

Kagome is able to pull out the Tetsusaiga. Sesshomaru tries to kill her, and Inuyasha is angered and fights to protect Kagome. His will to protect a human changes the Tetsusaiga into its true form, a fang sword.

In the Kai Province, there is a young samurai named Nobunaga. He is a clumsy but earnest young man. He has heard rumors about the man that the the princess, his childhood friend, has married. Nobunaga tries to save the lord of the castle who is possessed by a toad demon.