After 700 years the sword Sounga, who belonged to the Great Dog Demon, is unleashed, tearing a rift in the barrier between the underworld and the earth and stirring the restless souls.

The legendary sword, So'unga, which belonged to the Great Dog Demon, has been unleashed. It seeks to cover the Earth in an eternal Hell and end all life on it. Inuyasha must join forces with his hateful brother, Sesshoumaru, and put an end to the evil sword that once belonged to their father.—sandyyvette14