A seventh-century Chinese folk tale about two snake demons who assume human form and fall in love with the same man takes on a vivid new life in “White Snake,” an animated fantasy co-directed by Amp Wong and Ji Zhao. Even if you’re not familiar with the source material, this Chinese production provides plenty of supernatural thrills for the modern young adult.

A nightmarish early sequence establishes the movie’s tension between the ancient and the contemporary: A beautiful woman dressed in white is attacked by tentacles that seem to emerge from a black ink wash of the sort associated with traditional Asian calligraphy. These stark images suggest a woman imprisoned by her past.

That woman is Blanca, who has lost much of her memory, though she has foggy visions of a sister Verta. Wandering through a forest, Blanca is saved by the naive Xu Xuan, a snake catcher who tries to help Blanca figure out her identity. When he learns that Blanca is a snake demon in human form, he’s OK with that. “There’s lots of bad people with no tails,” he says. “So what if you have a tail?”

Thus an ancient story of good and evil becomes a 21st-century lesson in acceptance. But there’s another problem with Blanca’s identity: Dark forces have sent her to Earth to kill a general, but she’s not sure she wants to carry out those evil plans. Will the forces of good win out in the end?

“White Snake” is the second feature from the Chinese studio Light Chaser Animation. Its character designs are not all executed with equal skill. Blanca’s big, almond-shaped eyes are appropriate for a fairy tale princess, but Xu Xuan’s round features could have come out of any CG factory.

On the other hand, the background designs are gorgeous, whether they aim for photorealism or strive to build a psychedelic, magical dreamscape. And the demon forms are wildly imaginative — perhaps too much so for the children who seem to be the film’s target audience. (It’s distributed by GKIDS, which, despite its name, handles movies for both adult and family audiences.) A humorous talking dog may seem kid-friendly, but a three-headed crane and a two-faced fox spirit may be too creepy for the elementary school crowd.

This is the latest in a long line of movies that have adapted this legend. It doesn’t quite match up to director Tsui Hark’s even more inventive 1993 film “Green Snake,” which emphasized the Verta character (played with conniving seduction by Maggie Cheung). But while that live-action film can be jarring in its depiction of women as evil serpents, “White Snake” has more sympathy for its demons. They, after all, have a conscience.