Before long it becomes clear, however, that Jack (Andrew Robertson) isn't a narcissist. He is, rather, suffering an incestuous desire for his sister Julie (Charlotte Gainsbourg), an androgynous 17-year-old, and he has to make do with the family resemblance in the mirror. One day, while horsing around, Jack accidentally discovers that Julie may reciprocate his feeling. When their mother (Sinead Cusack) dies, leaving them orphans, they bury her in cement inside a metal locker in the cellar, to prevent the authorities from splitting up the kids. Suddenly, Jack and Julie are the man and woman of the family. Gulp.
No use denying it, The Cement Garden, which is based on Ian McEwan's 1978 novel, packs a punch. Unsurprisingly, it took Birkin many years to get any studio to consider touching it with a ten-foot pole. It isn't just that it's rather mild and cozy--some might say even exploitative and droolingly prurient--toward a subject which, after bestiality and cannibalism, is probably the major taboo of our society. It's also just plain depressing.
But neither is there any use denying that Birkin's direction, especially in the first half of the film, is impressive. It's hard not to be drawn into the terror, as well as the frightening, disturbing eroticism, of Jack's and Julie's hormonal vertigo. The absurdly desolate milieu, something akin to that of a Hal Hartley film, distances us from the unsavory implications of the plot, and there are moments of touching humor, most of them involving younger brother Tom (wonderfully played by the director's son, Ned Birkin), who is unembarrassed by his tendencies toward transvestism.
After about midpoint, though, The Cement Garden runs out of steam fast. Charlotte brings home a boyfriend, Derek (Jochen Horst), and Jack glowers at him endlessly while Derek becomes curious about the bad smell coming from the cellar. Derek behaves responsibly, but he's made so unattractive that he seems intended to suggest that Jack and Julie would be better off eschewing the outside world and sticking with each other. Incest and the disorienting sexuality of youth are terrible, upsetting subjects, but it isn't easy to make them dull. By romanticizing them, however, Birkin manages to do so.
What the world definitely does not need right now is another nubile teenage sex symbol, but we've got one, anyway, in the languidly sexy Gainsbourg (she's Andrew Birkin's niece). It's easy to see why Birkin, who wrote a book called J.M. Barrie and the Lost Boys, would be drawn to The Cement Garden--essentially, Jack's house is a grubby but parent-free Neverland, and Julie is Wendy plus hot glands.