Director Yang Chao says his film Chang Jiang Tu (Crosscurrent), shown in competition on Monday at the Berlin International Film Festival, is like a love poem for one of the most important rivers in China - and also one of its most damaged.

The film blends elements of the real and the surreal as it follows a quest by the young captain Gao Chun, played by Qin Hao, as he steers his decrepit hulk of a freighter up the 6,300-kilometer river to deliver a mysterious cargo.

He is also in pursuit of a beautiful young woman, An Lu (Xin Zhilei), who may or may not be a phantasm, and who appears at various places along the river, sometimes to make love to him, at other times to vanish from sight.