Hakujaden

As a young boy, Xu-Xian is forced to free his pet, a small snake. Unbeknownst to him, the snake is actually a young snake goddess named Bai-Niang and she is in love with him. Many years later, when they are both adults, the princess is magically transformed into a human and sets out to find her love. But the local wizard believes her to be a vampire, and banishes Xu-Xian from the village in order to save him. Xu-Xian's pet pandas Panda and Mimi set out to save him and bring him, in the process becoming leaders of an animal gang. (Source: ANN)

Based on the Chinese folktale "Legend of the White Snake". It's the first anime feature film in color. Only two voice actors were used, providing the voices for all the different parts. It is also one of the first three anime films to be released in America and the first anime in any shape or form to be released there.