Answer:
It starts out on Hori island. There are 5 children. The youngest of the 5 half-demons, little Ai, escapes the demons who imprisons them because she has not yet been marked. There, the demons discover she has ran away, and call upon their huge, turtle like demon brother named Gora to kill her. Then, of course, Inuyasha and their gang appear out of no where and a fiesty Inuyasha fights the huge demon. The whole rest of the story follows their journey to hori island to and fro, where several fighting scenes take place. An uncalled flashback to Inuyasha's past when he was with kikyo shows he has too been marked by Ryura (the leader of the demons) so now he is stuck there until he defeats all the demons. Another flashback goes to Sesshomaru's past, how his father's underlings were killed and he too was marked. Its not a great movie compared to the others, but it can be enjoyable. The artwork is quite pleasent to look at, although in the English version the mouths do not match the English words coming out.