Based on a 54-page short story by Eileen Chang, Ang Lee’s latest foray into forbidden love is as monotonous and disaffecting as Brokeback Mountain was gripping and immediate. It will be best known as the film for which Lee received the NC-17 rating, but its sex scenes are no more provocative or enlightening than those on HBO’s Tell Me You Love Me. (In both cases, it’s amazing how something so cold is expected to generate so much heat.) Set in Japanese-occupied Shanghai during the 1940s, Lust, Caution is a beautifully shot and painfully prolonged soap opera in which a Chinese actress with a patriotic theater troupe (Wang Chia-chih, played by Tang Wei) enlists to kill the head of the secret police (Mr. Yee, played by Tony Leung), who is collaborating with the Japanese. Several years after the plot initially goes awry—the wrong people were killed—Wang ingratiates herself into the Yee household, where she begins a torrid, often violent, affair with Mr. Yee, for whom there’s a fine line between romance and rape. What Chang wrote about eloquently and succinctly—how love can corrupt the noblest intentions—Lee and his writers lose in translation. They’re so enamored of the details that they often lose sight of their leads, whose relationship is all but buried till 105 minutes into a movie better boiled down to half its running time.