Ang Lee's new film Lust, Caution, set in l942 during the Japanese occupation of China, is about a dangerous affair between a young female resistance fighter and a top Chinese collaborator.

Lee, who won an Academy Award for Brokeback Mountain, says this was much more difficult subject to tackle — and much more personal.

The film, starring Tony Leung and Tang Wei and adapted from a short story by Eileen Chang, just won the Golden Lion award at the Venice Film Festival.

During World War II, a young village woman named Wong washes up at a big-city university and joins a drama troupe. The young men and women of the troupe decide to do something more practical with their national fervor than just rouse an audience to stand and shout, "China will not fail!" They hatch a scheme to plant Wong on a Chinese official who is a collaborator — and a torturer — so that they can assassinate him.

The first part of their plot works. But Wong and that official, Mr. Yi, also become ensnared in a brutal relationship that is deceitful on one part and savage on the other; and they both become increasingly vulnerable.

The "lust" of the film's title is so graphic — and often wrenching — that it drew an NC-17 rating.

Lee joins Scott Simon from member station KALW in San Francisco.