LEATHERCOAT Loudoun and Stuart Streets, The Plains, Va. 471-5327.

Open: Wednesday through Saturday 6 to 10 p.m., Sunday 5 to 9 p.m. Brunch is served Saturday and Sunday 11:30 a.m. to 2:30 p.m. V, AE, MC, D, Choice. Reservations suggested. Prices: at dinner, appetizers $5 to $10, main dishes $15 to $25, desserts about $6. Full dinner with wine, tax and tip about $50 to $60 a person.

It's not crocuses that are the first sign of spring for Washington, but the trail of cars to the country, in search of a good country inn. So it is time to look at Leathercoat, in The Plains, which has now weathered its first winter.

Leathercoat is a restaurant to be considered in context: it is as expensive as some of the top downtown restaurants and as far out of town as Little Washington's superb five-year-old inn. So what would draw one to this restaurant -- 50 miles from Washington -- for a $50 dinner?

Leathercoat has some obvious draws and more subtle drawbacks. Among the draws are furnishings of deceptively simple spindle-back handmade wood chairs and a wood interior with a well-oiled golden glow. The restaurant has several small dining rooms on two floors, each with a slightly different feel, from a sun porch atmosphere to a cozy nook. Everything from the blue-gray Limoges service plates to the fabric walls shows quality -- and expense. Something, though, falls short. The walls are unadorned, yet spotlights play on them as if they are waiting for paintings to arrive. A personal touch is missing.

One of the most luxurious resources of Leathercoat is its Cruvinet system for keeping wines fresh after they have been opened. Only a few restaurants in Washington have such an expensive gadget, and at Leathercoat it makes possible the serving of 26 different wines by the glass. The restaurant has also outfitted itself with a very competent wine buyer, for there is a broad and interesting selection of American wines in particular. Wines by the bottle sell here at some remarkably low prices (though one old wine I tried was not up to par, which made me wonder about its storage before Leathercoat acquired it). You can find an excellent California varietal for under $20, and some wines are priced below retail.

Not so with the food. It is for culinary adventurers, for there is no single plain old familiar dish on the menu. That's fine if people understand that they are not driving deep into Virginia for country cooking. They will find New Zealand Greenlip clams served with dabs of caviar butter, pernod almond butter and red pepper relish -- all delightful tastes, but the clams could just as well have been eliminated for the little one could taste them under the sauces. They will find a sirloin steak, but it will taste as smoky as barbecue from its garnish of julinned smoked duck and preserved tomato and its dark sauce finished with cognac and madeira. Even seemingly plain grilled shrimp are napped with orange lavender beurre blanc and garnished with grapefruit and orange sections spiked with jalapeno peppers.

Some of it works, but at these prices more of it should work. The menu changes frequently, so specific recommendations are difficult. And there is no obvious pattern to what this chef does well, so you have to play restaurant roulette.

To start, the salads have been particularly good choices, made with varied and very fresh greens -- radicchio, endive and such -- and excellent oils and vinegars. A warm salad of sweetbreads, snow peas, greens and melted goat cheese, for instance, was a vibrant beginning. And a cold plate of excellent smoked salmon and lovely gravlax edged in green herbs, accompanied by a crisp and tangy cucumber salad and fresh fruit, was refreshing to see and to eat. Among hot appetizers, poached oysters and pencil-thin flavorful asparagus were sparked with slices of truffle and minced herbs bedded on beet pasta. Even with all those tastes juxtaposed it blended admirably. But shrimp mousse piled on fresh artichoke bottoms tasted as if the flavor had been leached out of them both, and the two sauces (nantua and beurre blanc) forming a mosaic on the plate didn't save them on the palate. Other appetizers have tried unsuccessfully to join uncompromising tastes: red pepper pasta with scallops; lobster and white truffles; or ravioli with lobster, sweetbreads and tomato basil hash did no justice to the fine individual ingredients.

Main dishes also incorporate exotic combinations -- veal with langoustines, squab with lobster, fish with raspberry vinaigrette and wilted greens. (The most complex of all still leaves me shaking my head: homemade wild turkey ravioli with beets, asparagus, and girolles mushrooms in a basil pesto cream sauce, says the menu.) Duck, preserved as a confit and smoked, garnishes several dishes. Sometimes the combinations work, but often they seem random experiments.

The main dish that worked best for me was squab -- boneless breast roasted very rare -- with lobster and ravioli in a port and peppercorn sauce. The squab was perhaps too raw and the lobster had dried out a bit, but the sauce connected them in an interesting way. Garnishing the dishes, though, were ravioli -- thin and expertly fashioned -- whose filling was lost in that strong sauce and fresh clementines that could just have well been plain old oranges.

Even better was a simpler dish, a whole fish -- Mediterranean rouget -- stuffed with tomato basil hash and charcoal grilled, garnished with herbed butter. The fish looked beautiful, and the garden crunch and fragrance of the stuffing balanced the smokiness and emphasized the clean, fresh taste of the fish. The sirloin steak, on the other hand, was overwhelmed by all its accompanying flavors, and the meat itself, though cooked crusty and rare, lacked juiciness.

Ang with these dishes come fine crusty rolls and a variety of fresh vegetables, plus wild rice with pecans, cottage fries or flavored pasta. Such touches show how greatly the kitchen cares even if it does not always carry off its ambitions.

What is less commendable is that the kitchen is painfully slow. When one is faced with a drive home of an hour or more, a 31/2-hour dinner becomes an anxious evening.

Desserts also are experimental, with mixed success. Much as I love poppy seeds, they did nothing but add a branlike crunch to a chocolate torte; a plain old mocha mousse cake worked better, though it wouldn't draw a crowd. And chocolate truffles are good, but most restaurants of this caliber offer them free with coffee (which is here superb, brewed to order in Melior pots); at Leathercoat they cost $4.50 for three.

Service is enthusiastic and friendly, though often a dining room is left for long periods with nobody watching to see if service is needed. In all, Leathercoat is an expensive and enthusiastic brainstorm of a restaurant. But its adventurous ideas need honing.

-- Phyllis Chasanow-Richman