It's a French site but they usually have a short English summary at the end of their articles.

Plot Summary: Although antique stories are popular among Chinese animation works in recent years, "Deep Sea" will apply a different way, using unique oriental aesthetics to interpret a fantasy story with a modern background.

The film "Deep Sea" builds a different brand new underwater world, and tells the story of a girl who encounters a unique life journey, seeking and searching in the mysterious underwater world.

The images such as the huge maelstroms, peculiar fishes, eyes in the maelstroms that present in the poster, all demonstrate the iceberg tip of the "Deep Sea" world. The posture of the leading girl swimming into the maelstrom firmly just acknowledges the slogan on the poster -- "Where the heart goes is deeper than the sea."

English audience : "Deep Sea", an upcoming chinese animated feature film by Tian Xiaopeng (Monkey King: Hero Is Back). Produced by Coloroom Pictures and October Media, using a really oriental artistic direction.

The animation sample they showed looked really good. I can't tell if it's 2D or 3D, I'm guessing 3D from the director's past work.