In the movies, thoroughly imagined works of naturalism are as rare as truly devastating-consolatory works of tragedy. A superficially naturalistic handling is so common, however, that romance, comedy, and melodrama are more often than not discussed in terms appropriate to naturalism. People commonly talk about the heroes of romance as if they, too, were people, when, in truth, a romance hero's solely meaningful motivation is to champion good against evil. Although such evil is often cloaked in a contemporary issue, it needn't be, and almost never is, naturalistically depicted. The structure and aims of romance thus make that genre readily translatable from context to context (country, period, topic).

By contrast, a naturalistic story is rooted in its specific, material context and reaches for a far more modest and scrupulously craftsmanlike end: What would these recognizable characters plausibly do in this situation that they have believably got themselves into? Other genres can be handled naturalistically, and naturalism can incorporate elements of other genres, but when a work is as palpably built up from acute observation as Julian Fellowes's Separate Lies (or John Curran's We Don't Live Here Anymore (2004) or Bo Goldman and Alan Parker's Shoot the Moon (1982)), you're responding to what naturalism brings to narrative. You can feel your brain being called to attend to every word, gesture, interaction, object, setting, for the significance they carry in themselves.

Fellowes has updated Nigel Balchin's 1950 novel A Way Through the Wood: James Manning (Tom Wilkinson), a successful London solicitor, suspects that Bill Bule (Rupert Everett), a nobleman who lives near Manning's country getaway, is the unknown person who struck the husband of Manning's housekeeper Maggie (Linda Bassett) with his Land Rover. It's a bit sticky because at the time of the accident Bule would have been en route to a party given by Manning's wife Anne (Emily Watson). But James, man of principle, gets Bule to admit his responsibility over lunch and then presses him to turn himself into the police. (Principle does not, however, suggest to James that he need visit the fatally wounded man in the hospital; Anne has to drag him.) James adopts an unbending moral stance when he tells Anne about his lunch with Bule, but in this conversation with his wife he finds out details about the accident that he would rather not have known. High-minded as James is--a "boy scout," in Bule's words--he immediately reverses course and wants to cover the incident up. But it's too late: he has stirred up Anne's moral sensibilities, though in a less straightforward way than he envisioned, and the cracks in their marriage become fissures.

Separate Lies is, first of all, a completely convincing portrait of a functioning comfortless marriage. Anne has always felt she can't measure up to James's expectations, and we can see, as Anne herself can, that she is not particularly accomplished at running his households. She might fare better but James's supervision undermines her confidence, and then when she inevitably falls short he steps in and "manages" her as if she were an employee. (One much less efficient than his secretary.) Anne may in some social sense be raised in importance by having a powerful husband who can afford choice property, but her spirit is lowered by his nitpicking. In addition, James doesn't particularly want to socialize after working all day all week, which too often puts Anne in the position of having no one but her hypercritical husband for company.