In the early '70s, Bernardo Bertolucci made a radically erotic movie called "Last Tango in Paris." It was about two isolated lovers in an apartment in a cosmopolitan European capital who push each other (and the audience) beyond the limits with their ardor.

Now Bertolucci's back in an apartment in a cosmopolitan European capital with two isolated lovers, but the results are different in strange, almost lovely, ways. For "Besieged" isn't erotic at all, but it's sensual in that it celebrates not the flesh but the world with all its stimulations and possibilities. It's a film whose signature value is its palpable immediacy: It puts you there with great power.

"There" happens to be a house in Rome. Upstairs in a shabby but magnificent apartment lives the strange and furtive Mr. Kinsky (David Thewlis). Downstairs lives the passionate Shandurai (luminous Thandie Newton), who pays for her rent and her medical education by keeping house for him.

But unlike Marlon Brando and Maria Schneider in "Last Tango," these two do not flee the universe outside for the universe inside. Each, in fact, is besieged by the outside, and that entrapment turns their love life from erotic to tentative.

The movie watches them fumble toward each other in clumsy ways, the groping attraction-repulsion dance played out in all its squalid glory as each tries to find a bridge to the other. It is even ambiguous on the issue of sex (something "Last Tango" certainly wasn't), leaving open the possibility that consummation may not have been achieved.

She is besieged by memories and politics: The arrest and imprisonment of her husband in a decaying, unnamed African country are always on her mind.

What besieges him? We are less sure. He's a self-hating composer who inherited the house from a mysterious wife. When he's not hating himself for not being good enough, he makes a living teaching piano to children.

Is there any stranger movie creature than David Thewlis? With that lumpy mouth and those splayed, ugly teeth and with a chin that flees to the horizon like a running bunny, and his bony nose and a thatch of hair, he's almost more specter than man, a gangly haunt. But he's so awkward and unversed in love that he's almost sweet instead of creepy.

The story unfolds from her viewpoint, so we're never certain what he's up to. His strangest behavior is to begin stripping the apartment of its antiques, again for ambiguous reasons. But soon she realizes he is selling everything to finance some project. She begins to suspect that she's at the center of his plans, but in what sense, she's unsure.

This movie turns out not to be about sex at all, which Bertolucci in his maturity now seems to feel is common. Rather, it's about something much more valuable and harder to capture: love. For in a way, Mr. Kinsky is committing suicide out of love. He is gradually sacrificing his life for her happiness, a gesture that can only have an unhappy ending for him, but fills one with a sense of gratitude.

It's a moving and beautiful movie that gives up its meanings grudgingly, but in the end it appears to be about a kind of selfless sacrifice rarely celebrated in the picture shows anymore.

Besieged (92 minutes, at the Cineplex Odeon Outer Circle 2 and the Cineplex Odeon Shirlington 7) is rated R for sexual suggestiveness.

CAPTION: David Thewlis as the failed composer enamored of a tenant (Thandie Newton) in his Rome apartment house in Bernardo Bertolucci's "Besieged."